From 6c708481b2db35f1608c15bf5b1a89f7caf85cc6 Mon Sep 17 00:00:00 2001 From: Douglas Q Hawkins Date: Wed, 15 Jul 2026 16:30:58 -0400 Subject: [PATCH] Store known span tags densely in TagMap by tag-id MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Known tags (keyOf resolves to a stored id) are held in insertion-ordered parallel arrays (knownIds/knownValues) with NO per-tag Entry object — the allocation lever. Lazily allocated on the first known-tag write; custom tags stay in the hash buckets. Disjoint by construction (known-ness is global), so read-through shadow checks stay within-region and the bucket path is unchanged. - KnownTagCodec (id encoding + resolver) + hand-written KnownTags (keyOf substrate over StringIndex). Off-by-default: dormant until a resolver registers, so production is byte-identical. - CoreTracer flips it live behind `-Ddd.trace.dense.tags.enabled` for A/B. - Sizing is a generous fixed stopgap (KNOWN_INIT_CAP=12, the per-type max); exact per-type sizing comes with the tag registry. Reconciled onto the level-split stack (fold + read-through + StringIndex); built on the folded final-class TagMap. Co-Authored-By: Claude Opus 4.8 --- .../java/datadog/trace/core/CoreTracer.java | 9 + .../trace/api/DenseStoreAllocBenchmark.java | 148 +++++ .../java/datadog/trace/api/KnownTagCodec.java | 177 ++++++ .../java/datadog/trace/api/KnownTags.java | 326 +++++++++++ .../main/java/datadog/trace/api/TagMap.java | 504 +++++++++++++++--- .../java/datadog/trace/api/KnownTagsTest.java | 152 ++++++ .../trace/api/TagMapDenseForkedTest.java | 273 ++++++++++ .../trace/api/TagMapDenseFuzzForkedTest.java | 202 +++++++ 8 files changed, 1729 insertions(+), 62 deletions(-) create mode 100644 internal-api/src/jmh/java/datadog/trace/api/DenseStoreAllocBenchmark.java create mode 100644 internal-api/src/main/java/datadog/trace/api/KnownTagCodec.java create mode 100644 internal-api/src/main/java/datadog/trace/api/KnownTags.java create mode 100644 internal-api/src/test/java/datadog/trace/api/KnownTagsTest.java create mode 100644 internal-api/src/test/java/datadog/trace/api/TagMapDenseForkedTest.java create mode 100644 internal-api/src/test/java/datadog/trace/api/TagMapDenseFuzzForkedTest.java diff --git a/dd-trace-core/src/main/java/datadog/trace/core/CoreTracer.java b/dd-trace-core/src/main/java/datadog/trace/core/CoreTracer.java index 74737d0bee4..c9738a15360 100644 --- a/dd-trace-core/src/main/java/datadog/trace/core/CoreTracer.java +++ b/dd-trace-core/src/main/java/datadog/trace/core/CoreTracer.java @@ -37,6 +37,7 @@ import datadog.trace.api.EndpointTracker; import datadog.trace.api.IdGenerationStrategy; import datadog.trace.api.InstrumenterConfig; +import datadog.trace.api.KnownTags; import datadog.trace.api.Pair; import datadog.trace.api.TagMap; import datadog.trace.api.TraceConfig; @@ -653,6 +654,14 @@ private CoreTracer( // preload this enum to avoid triggering classloading on the hot path TraceCollector.PublishState.values(); + // Dense known-tag store (experimental, OFF by default): registering the KnownTagCodec resolver + // flips the dense store live so known tags store without a per-tag Entry. Gated by a system + // property for A/B benchmarking; when off, keyOf stays a no-op and tag storage is byte-identical + // to today. Promote to a Config flag if this becomes a permanent rollout. + if (Boolean.getBoolean("dd.trace.dense.tags.enabled")) { + KnownTags.init(); + } + if (reportInTracerFlare) { TracerFlare.addReporter(this); } diff --git a/internal-api/src/jmh/java/datadog/trace/api/DenseStoreAllocBenchmark.java b/internal-api/src/jmh/java/datadog/trace/api/DenseStoreAllocBenchmark.java new file mode 100644 index 00000000000..6c11f8bc212 --- /dev/null +++ b/internal-api/src/jmh/java/datadog/trace/api/DenseStoreAllocBenchmark.java @@ -0,0 +1,148 @@ +package datadog.trace.api; + +import datadog.trace.bootstrap.instrumentation.api.Tags; +import java.util.concurrent.TimeUnit; +import org.openjdk.jmh.annotations.Benchmark; +import org.openjdk.jmh.annotations.BenchmarkMode; +import org.openjdk.jmh.annotations.Fork; +import org.openjdk.jmh.annotations.Level; +import org.openjdk.jmh.annotations.Measurement; +import org.openjdk.jmh.annotations.Mode; +import org.openjdk.jmh.annotations.OutputTimeUnit; +import org.openjdk.jmh.annotations.Param; +import org.openjdk.jmh.annotations.Scope; +import org.openjdk.jmh.annotations.Setup; +import org.openjdk.jmh.annotations.State; +import org.openjdk.jmh.annotations.Threads; +import org.openjdk.jmh.annotations.Warmup; +import org.openjdk.jmh.infra.Blackhole; + +/** + * Deterministic allocation A/B for the dense known-tag store, using the REAL {@link KnownTags} + * resolver (a {@code StringIndex} probe + a constant-returning {@code switch} — allocation-free, + * exactly like production). An earlier synthetic prefix resolver allocated in {@code keyOf} + * (substring) and {@code nameOf} (concat), contaminating the dense arm; this measures the store, + * not the resolver. + * + *

Models how a real span's tags route: {@code today} = all custom (what ships now — every tag + * buckets, since nothing is registered as known), {@code dense} = the same tag count with a + * realistic fraction routed to the dense store (real known tag names) and the rest custom. Run with + * {@code -prof gc}; the {@code gc.alloc.rate.norm} (B/op) delta at the same {@code tagCount} is + * what enabling the dense store does to a real span's per-build allocation. + * + *

Results — buildMap, JDK 17 (Zulu 17.0.7, Apple Silicon), {@code -prof gc -f 1 -wi 2 -i 3}, + * 2026-07-08. Allocation is deterministic (±0.001 B/op); throughput on this run is NOT + * trustworthy (single fork, short) — read B/op only. + * + * 

{@code
+ * scenario    tagCount=7   tagCount=12
+ * today          408 B/op     704 B/op
+ * dense          376 B/op     416 B/op
+ * allKnown       176 B/op     400 B/op
+ * }
+ * + *

Gate met: {@code dense < today} at both counts (the over-provision artifact is gone). The + * Entry-less win scales with the known-tag fraction — ~8% at 7 tags (~70% known), ~41% at 12; + * {@code allKnown} (the codegen endgame / read-through parent shape) reaches ~57% at 7. + * + *

Serialize paths (same run, B/op). {@code buildAndSerialize} (alloc-free {@code forEach} + * flyweight) adds a flat +16 B/op over {@code buildMap} in every scenario (7: 392, 12: 432 dense). + * {@code buildAndSerializeViaIterator} — the {@code EntryReader} enhanced-for modeling the count + * pre-pass at {@code TraceMapperV0_4:95} — adds a CONSTANT per-call cost (+56 custom / +80 dense, + * identical at 7 and 12 tags): that flat-vs-tagCount signature is the {@code EntryReaderIterator} + * OBJECT, NOT per-tag Entry — the iterator reuses a dense flyweight (TagMap:2182/2652). So the + * dense win SURVIVES serialization; the only nit is {@code iterator()} allocating one Iterator per + * call, which {@code forEach} avoids and which can be recycled away. + */ +@State(Scope.Benchmark) +@BenchmarkMode(Mode.Throughput) +@OutputTimeUnit(TimeUnit.SECONDS) +@Warmup(iterations = 2, time = 2) +@Measurement(iterations = 3, time = 2) +@Fork(1) +@Threads(1) +public class DenseStoreAllocBenchmark { + + // Real stored (dense-routed) tag names — a realistic web/db span's known set. + static final String[] KNOWN = + new String[] { + DDTags.BASE_SERVICE, + Tags.VERSION, + Tags.COMPONENT, + Tags.SPAN_KIND, + Tags.HTTP_METHOD, + Tags.HTTP_ROUTE, + Tags.DB_TYPE, + Tags.DB_INSTANCE, + Tags.PEER_HOSTNAME, + Tags.DB_USER, + DDTags.LANGUAGE_TAG_KEY, + Tags.PEER_PORT, + }; + + // today = all custom (all bucket, what ships now); dense = ~70% known + custom (a real span); + // allKnown = 100% known (the trace-tier read-through parent's shape — exercises lazy buckets). + @Param({"today", "dense", "allKnown"}) + String scenario; + + @Param({"7", "12"}) + int tagCount; + + private String[] keys; + private String[] values; + + @Setup(Level.Trial) + public void setup() { + KnownTags.init(); // registers the real (allocation-free) resolver + int knownCount; + if ("allKnown".equals(scenario)) { + knownCount = tagCount; // 100% known (<= KNOWN.length) + } else if ("dense".equals(scenario)) { + knownCount = (tagCount * 7) / 10; // ~70% known + custom + } else { + knownCount = 0; // today: all custom (all bucket) + } + this.keys = new String[tagCount]; + this.values = new String[tagCount]; + for (int i = 0; i < tagCount; i++) { + this.keys[i] = i < knownCount ? KNOWN[i] : "custom.tag." + i; + this.values[i] = "value-" + i; + } + } + + @Benchmark + public TagMap buildMap() { + TagMap m = TagMap.create(16); + for (int i = 0; i < tagCount; i++) { + m.set(keys[i], values[i]); + } + return m; + } + + @Benchmark + public void buildAndSerialize(Blackhole bh) { + TagMap m = TagMap.create(16); + for (int i = 0; i < tagCount; i++) { + m.set(keys[i], values[i]); + } + // forEach: the alloc-free flyweight emit for dense + m.forEach(reader -> bh.consume(reader.objectValue())); + bh.consume(m); + } + + @Benchmark + public void buildAndSerializeViaIterator(Blackhole bh) { + TagMap m = TagMap.create(16); + for (int i = 0; i < tagCount; i++) { + m.set(keys[i], values[i]); + } + // models the REAL serializer's count pre-pass (TraceMapperV0_4:95). The EntryReader iterator + // uses a reused dense flyweight (NO per-tag Entry alloc — TagMap:2182/2652), so the dense win + // SURVIVES; the only extra cost vs forEach is the EntryReaderIterator object itself (a fixed + // per-call cost, constant across tagCount — not per-tag). forEach avoids even that. + for (TagMap.EntryReader reader : m) { + bh.consume(reader.objectValue()); + } + bh.consume(m); + } +} diff --git a/internal-api/src/main/java/datadog/trace/api/KnownTagCodec.java b/internal-api/src/main/java/datadog/trace/api/KnownTagCodec.java new file mode 100644 index 00000000000..7ed9dff633a --- /dev/null +++ b/internal-api/src/main/java/datadog/trace/api/KnownTagCodec.java @@ -0,0 +1,177 @@ +package datadog.trace.api; + +import edu.umd.cs.findbugs.annotations.SuppressFBWarnings; + +/** + * Registry for generated tag ID ↔ name resolution. The code generator populates this at tracer init + * via {@link #register(Resolver)}. Once registered, HotSpot CHA devirtualizes and inlines the + * resolver's switch, making {@link #nameOf}/{@link #keyOf} effectively zero-overhead. + */ +public final class KnownTagCodec { + // Plain (non-volatile) fast-path flag: false until a resolver is ever registered. A plain read is + // free and hoistable, unlike a volatile read of `resolver` (costly on weak memory models such as + // ARM). A stale `false` is benign — callers treat the tag as unknown and use the hash buckets, + // which is correct, just unoptimized; the next read after publication takes the slot path. + private static boolean active; + + private static volatile Resolver resolver; + + /** Fast-path gate: true once a resolver has been registered. */ + public static boolean isActive() { + return active; + } + + /* + * tagId bit layout: [63 intercepted] [62-48 globalSerial (15 bits)] [47-32 fieldPos] + * [31-0 nameHash]. Bit 63 (the sign bit) marks a tag the tag interceptor must see, so the check + * is a single {@code tagId < 0}. globalSerial is globally unique per known tag; fieldPos is its + * slot in the global positional layout (TagMap.knownEntries index); nameHash is + * TagMap.Entry#_hash(name) and is layout-independent. Unknown (string-only) tags have the upper + * 32 bits zero. NOTE: TagMap.Entry decodes nameHash inline as (int) tagId on its hot path, so the + * low-32 encoding here must stay in sync with that. + */ + public static int globalSerial(long tagId) { + return (int) ((tagId >>> 48) & 0x7FFF); + } + + /** + * Flag bit (the sign bit) marking a tag the tag interceptor must process — reserved/"virtual" + * tags AND intercepted-but-stored tags (e.g. http.method, which the interceptor side-effects and + * also stores). Encoded in the id so {@code DDSpanContext.setTag(long)} can route with a single + * sign test ({@link #isIntercepted}) instead of resolving the name. Non-intercepted tags (peer.*, + * base.service, …) leave it clear and take the fast store path. Must agree with the interceptor's + * name-based {@code needsIntercept} for every assigned id. + */ + public static final long INTERCEPTED = Long.MIN_VALUE; // 1L << 63 + + /** True if the tagId is flagged for tag-interceptor processing. */ + public static boolean isIntercepted(long tagId) { + return tagId < 0L; + } + + /** Returns the tagId with the {@link #INTERCEPTED} flag set. */ + public static long intercepted(long tagId) { + return tagId | INTERCEPTED; + } + + public static int fieldPos(long tagId) { + return (int) ((tagId >>> 32) & 0xFFFF); + } + + public static int nameHash(long tagId) { + return (int) tagId; + } + + /** + * globalSerial partition. {@code [1, FIRST_STORED_SERIAL)} is reserved for "virtual" tags that + * are specially handled (redirected to span fields or processed by the tag interceptor) and are + * NOT stored in the TagMap — these are hand-assigned in tracer core. {@code [FIRST_STORED_SERIAL, + * ..]} is for generated convention tags that ARE stored (slotted/bucketed). {@code globalSerial + * == 0} means unknown / string-only. Both core and the code generator must agree on this + * boundary. + */ + public static final int FIRST_STORED_SERIAL = 256; + + /** True if the tagId names a reserved "virtual"/specially-handled tag (not stored in the map). */ + public static boolean isReserved(long tagId) { + int globalSerial = globalSerial(tagId); + return globalSerial > 0 && globalSerial < FIRST_STORED_SERIAL; + } + + /** True if the tagId names a generated, map-stored (slotted/bucketed) tag. */ + public static boolean isStored(long tagId) { + return globalSerial(tagId) >= FIRST_STORED_SERIAL; + } + + /** + * Sentinel {@code fieldPos} meaning "no positional slot". It is the maximum value the 16-bit + * fieldPos field can hold, so it always compares {@code >= slotCount()} and routes to the hash + * buckets rather than the fast positional array. Two kinds of tagId use it: + * + *

+ */ + public static final int NO_SLOT = 0xFFFF; + + /** + * True if the tagId names a stored tag that deliberately has no positional slot (bucket-only). + */ + public static boolean isUnslotted(long tagId) { + return isStored(tagId) && fieldPos(tagId) == NO_SLOT; + } + + /** + * Builds a tagId from its parts: {@code globalSerial} (globally unique per known tag), {@code + * fieldPos} (the tag's slot within its span type's positional table), and the tag {@code name} + * (whose hash is computed via the same function the runtime uses, so the low 32 bits match {@link + * TagMap.Entry#hash()}). Inverse of {@link #globalSerial}/{@link #fieldPos}/{@link #nameHash}. + * Intended for the code generator and tests. + */ + public static long tagId(int globalSerial, int fieldPos, String name) { + long nameHash = TagMap.Entry._hash(name) & 0xFFFFFFFFL; + return ((long) globalSerial << 48) | ((long) (fieldPos & 0xFFFF) << 32) | nameHash; + } + + /** + * Builds a tagId with no positional slot ({@code fieldPos == }{@link #NO_SLOT}). Use for reserved + * "virtual" tags and for "low-priority" stored tags that get a stable id but are intentionally + * kept out of the fast slot array (they route to the hash buckets). See {@link #NO_SLOT}. + */ + public static long tagId(int globalSerial, String name) { + return tagId(globalSerial, NO_SLOT, name); + } + + // Number of positional slots in the global layout = (max stored fieldPos) + 1, declared by the + // registered provider. Captured once at registration and read as a dynamic constant; TagMap sizes + // its knownEntries array to exactly this rather than a hardcoded max. 0 when no resolver. + private static int slotCount; + + /** Slot count of the registered provider (max stored fieldPos + 1); 0 if none. */ + public static int slotCount() { + return slotCount; + } + + public interface Resolver { + String nameOf(long tagId); + + long keyOf(String name); + + /** Number of positional slots this provider uses: (max stored fieldPos) + 1. */ + int slotCount(); + } + + @SuppressFBWarnings( + value = "AT_STALE_THREAD_WRITE_OF_PRIMITIVE", + justification = + "active/slotCount are plain by design: written once at tracer-init registration (before" + + " any span processing) and read plain on the hot path. A stale read is benign — the" + + " tag is treated as unknown and takes the hash-bucket path — so plain reads are" + + " deliberately preferred over a costly volatile read on weak memory models.") + public static void register(Resolver resolver) { + KnownTagCodec.resolver = resolver; // volatile write publishes the resolver + KnownTagCodec.slotCount = (resolver != null) ? resolver.slotCount() : 0; + KnownTagCodec.active = + (resolver != null); // plain write; readers re-read resolver volatile anyway + } + + public static String nameOf(long tagId) { + if (!active) return null; + Resolver r = resolver; + return r != null ? r.nameOf(tagId) : null; + } + + public static long keyOf(String name) { + if (!active) return 0L; + Resolver r = resolver; + return r != null ? r.keyOf(name) : 0L; + } + + private KnownTagCodec() {} +} diff --git a/internal-api/src/main/java/datadog/trace/api/KnownTags.java b/internal-api/src/main/java/datadog/trace/api/KnownTags.java new file mode 100644 index 00000000000..3a702eae38d --- /dev/null +++ b/internal-api/src/main/java/datadog/trace/api/KnownTags.java @@ -0,0 +1,326 @@ +package datadog.trace.api; + +import datadog.trace.bootstrap.instrumentation.api.Tags; +import datadog.trace.util.StringIndex; + +/** + * Hand-assigned tag-id constants for well-known tags, plus the {@link KnownTagCodec.Resolver} that + * resolves them. This is the single registry shared by the tracer core and by instrumentation + * (decorators) — it lives in {@code internal-api} so both layers can reference the ids; the + * eventual code generator will replace the hand assignment here. + * + *

Reserved serials {@code [1, KnownTagCodec.FIRST_STORED_SERIAL)} name "virtual" tags handled by + * the tag interceptor / span fields and are NOT stored in the {@code TagMap}; their {@code + * fieldPos} is the {@link KnownTagCodec#NO_SLOT} sentinel that is out of slot range, so any + * incidental store routes to the hash buckets rather than a positional slot. Serials {@code >= + * FIRST_STORED_SERIAL} name stored tags that slot/bucket normally (or, with {@code NO_SLOT}, are + * stored bucket-only). + * + *

The resolver registers on class initialization, so simply referencing any constant here makes + * tag-id resolution live before the first span is built. + * + *

Slice-1 note (keyOf substrate): the {@code fieldPos} assignments below (and {@link + * #SLOT_COUNT}) describe a single universal positional layout (slots 0..25). That layout is + * currently dormant — no dense store consumes {@code fieldPos} yet — and is provisional: the + * dense-store slice replaces the universal layout with per-role / per-type sizing (see the + * over-provision finding in {@code dense-tagmap-design.md}). {@code keyOf}/{@code nameOf} depend + * only on {@code globalSerial} + name, not {@code fieldPos}, so the ids themselves are stable + * across any layout scheme. + */ +public final class KnownTags { + // slot count = (max stored fieldPos) + 1. Stored tags use fieldPos 0..25. PROVISIONAL universal + // layout — see the slice-1 note above; the dense-store slice supersedes this with role/type + // sizing. + static final int SLOT_COUNT = 26; + + // ---- reserved / virtual (tag-interceptor handled, not stored) ---- + // Reserved tags are always intercepted -> set the INTERCEPTED flag. + public static final int ERROR_SERIAL = 1; + public static final long ERROR_ID = + KnownTagCodec.intercepted(KnownTagCodec.tagId(ERROR_SERIAL, Tags.ERROR)); + + // ---- stored (slotted / bucketed) ---- + public static final int PARENT_ID_SERIAL = KnownTagCodec.FIRST_STORED_SERIAL; + public static final long PARENT_ID = KnownTagCodec.tagId(PARENT_ID_SERIAL, 0, DDTags.PARENT_ID); + + // common (process-constant) tags added by InternalTagsAdder to ~every span + public static final int BASE_SERVICE_SERIAL = KnownTagCodec.FIRST_STORED_SERIAL + 1; + public static final long BASE_SERVICE_ID = + KnownTagCodec.tagId(BASE_SERVICE_SERIAL, 1, DDTags.BASE_SERVICE); + + public static final int VERSION_SERIAL = KnownTagCodec.FIRST_STORED_SERIAL + 2; + public static final long VERSION_ID = KnownTagCodec.tagId(VERSION_SERIAL, 2, Tags.VERSION); + + // build-time-known constant tags merged into defaultSpanTags (see CoreTracer.withTracerTags). + // "env" is a base-mixin tag; the *_ENABLED flags are product-mixin tags. Hand-assigned for now. + public static final String ENV = "env"; + public static final int ENV_SERIAL = KnownTagCodec.FIRST_STORED_SERIAL + 3; + public static final long ENV_ID = KnownTagCodec.tagId(ENV_SERIAL, 3, ENV); + + public static final int DJM_ENABLED_SERIAL = KnownTagCodec.FIRST_STORED_SERIAL + 4; + public static final long DJM_ENABLED_ID = + KnownTagCodec.tagId(DJM_ENABLED_SERIAL, 4, DDTags.DJM_ENABLED); + + public static final int DSM_ENABLED_SERIAL = KnownTagCodec.FIRST_STORED_SERIAL + 5; + public static final long DSM_ENABLED_ID = + KnownTagCodec.tagId(DSM_ENABLED_SERIAL, 5, DDTags.DSM_ENABLED); + + // common tags added by the tag post-processors (RemoteHostnameAdder / IntegrationAdder / + // ServiceNameSourceAdder). Not intercepted; stored. + public static final int TRACER_HOST_SERIAL = KnownTagCodec.FIRST_STORED_SERIAL + 6; + public static final long TRACER_HOST_ID = + KnownTagCodec.tagId(TRACER_HOST_SERIAL, 6, DDTags.TRACER_HOST); + + public static final int INTEGRATION_SERIAL = KnownTagCodec.FIRST_STORED_SERIAL + 7; + public static final long INTEGRATION_ID = + KnownTagCodec.tagId(INTEGRATION_SERIAL, 7, DDTags.DD_INTEGRATION); + + public static final int SVC_SRC_SERIAL = KnownTagCodec.FIRST_STORED_SERIAL + 8; + public static final long SVC_SRC_ID = KnownTagCodec.tagId(SVC_SRC_SERIAL, 8, DDTags.DD_SVC_SRC); + + // peer.service tags, read/written by PeerServiceCalculator (post-processor; uses Map put/get that + // bypass the interceptor). peer.service is intercepted on the set-path but STORED, so it slots. + public static final int PEER_SERVICE_SERIAL = KnownTagCodec.FIRST_STORED_SERIAL + 9; + public static final long PEER_SERVICE_ID = + KnownTagCodec.intercepted(KnownTagCodec.tagId(PEER_SERVICE_SERIAL, 9, Tags.PEER_SERVICE)); + + public static final int PEER_SERVICE_REMAPPED_FROM_SERIAL = + KnownTagCodec.FIRST_STORED_SERIAL + 10; + public static final long PEER_SERVICE_REMAPPED_FROM_ID = + KnownTagCodec.tagId(PEER_SERVICE_REMAPPED_FROM_SERIAL, 10, DDTags.PEER_SERVICE_REMAPPED_FROM); + + // HTTP tags read by HttpEndpointPostProcessor. http.method/http.url are intercepted-but-stored + // (interceptTag side-effects then returns false → stored); http.route is not intercepted. All + // stored, so the string set-path slots them via keyOf and the id reads here find them. + public static final int HTTP_METHOD_SERIAL = KnownTagCodec.FIRST_STORED_SERIAL + 11; + public static final long HTTP_METHOD_ID = + KnownTagCodec.intercepted(KnownTagCodec.tagId(HTTP_METHOD_SERIAL, 11, Tags.HTTP_METHOD)); + + public static final int HTTP_ROUTE_SERIAL = KnownTagCodec.FIRST_STORED_SERIAL + 12; + public static final long HTTP_ROUTE_ID = + KnownTagCodec.tagId(HTTP_ROUTE_SERIAL, 12, Tags.HTTP_ROUTE); + + public static final int HTTP_URL_SERIAL = KnownTagCodec.FIRST_STORED_SERIAL + 13; + public static final long HTTP_URL_ID = + KnownTagCodec.intercepted(KnownTagCodec.tagId(HTTP_URL_SERIAL, 13, Tags.HTTP_URL)); + + // peer connection tags set by BaseDecorator.onPeerConnection on ~every client/producer span. + // Not intercepted; stored. Slotted (common across client instrumentations). + public static final int PEER_HOSTNAME_SERIAL = KnownTagCodec.FIRST_STORED_SERIAL + 14; + public static final long PEER_HOSTNAME_ID = + KnownTagCodec.tagId(PEER_HOSTNAME_SERIAL, 14, Tags.PEER_HOSTNAME); + + public static final int PEER_HOST_IPV4_SERIAL = KnownTagCodec.FIRST_STORED_SERIAL + 15; + public static final long PEER_HOST_IPV4_ID = + KnownTagCodec.tagId(PEER_HOST_IPV4_SERIAL, 15, Tags.PEER_HOST_IPV4); + + public static final int PEER_HOST_IPV6_SERIAL = KnownTagCodec.FIRST_STORED_SERIAL + 16; + public static final long PEER_HOST_IPV6_ID = + KnownTagCodec.tagId(PEER_HOST_IPV6_SERIAL, 16, Tags.PEER_HOST_IPV6); + + public static final int PEER_PORT_SERIAL = KnownTagCodec.FIRST_STORED_SERIAL + 17; + public static final long PEER_PORT_ID = KnownTagCodec.tagId(PEER_PORT_SERIAL, 17, Tags.PEER_PORT); + + // Universal decorator tags — set on ~every span (component/span.kind via Base/Server/Client + // decorators, language via ServerDecorator). span.kind is intercepted (setSpanKindOrdinal). + public static final int COMPONENT_SERIAL = KnownTagCodec.FIRST_STORED_SERIAL + 18; + public static final long COMPONENT_ID = KnownTagCodec.tagId(COMPONENT_SERIAL, 18, Tags.COMPONENT); + + public static final int SPAN_KIND_SERIAL = KnownTagCodec.FIRST_STORED_SERIAL + 19; + public static final long SPAN_KIND_ID = + KnownTagCodec.intercepted(KnownTagCodec.tagId(SPAN_KIND_SERIAL, 19, Tags.SPAN_KIND)); + + public static final int LANGUAGE_SERIAL = KnownTagCodec.FIRST_STORED_SERIAL + 20; + public static final long LANGUAGE_ID = + KnownTagCodec.tagId(LANGUAGE_SERIAL, 20, DDTags.LANGUAGE_TAG_KEY); + + // JDBC / database-client tags — set on every db span (58% of petclinic spans). Not intercepted + // (only db.statement is, and that's handled separately). + public static final int DB_TYPE_SERIAL = KnownTagCodec.FIRST_STORED_SERIAL + 21; + public static final long DB_TYPE_ID = KnownTagCodec.tagId(DB_TYPE_SERIAL, 21, Tags.DB_TYPE); + + public static final int DB_INSTANCE_SERIAL = KnownTagCodec.FIRST_STORED_SERIAL + 22; + public static final long DB_INSTANCE_ID = + KnownTagCodec.tagId(DB_INSTANCE_SERIAL, 22, Tags.DB_INSTANCE); + + public static final int DB_USER_SERIAL = KnownTagCodec.FIRST_STORED_SERIAL + 23; + public static final long DB_USER_ID = KnownTagCodec.tagId(DB_USER_SERIAL, 23, Tags.DB_USER); + + public static final int DB_OPERATION_SERIAL = KnownTagCodec.FIRST_STORED_SERIAL + 24; + public static final long DB_OPERATION_ID = + KnownTagCodec.tagId(DB_OPERATION_SERIAL, 24, Tags.DB_OPERATION); + + public static final int DB_POOL_NAME_SERIAL = KnownTagCodec.FIRST_STORED_SERIAL + 25; + public static final long DB_POOL_NAME_ID = + KnownTagCodec.tagId(DB_POOL_NAME_SERIAL, 25, Tags.DB_POOL_NAME); + + // Open-addressed name -> id table backing keyOf (data, not a switch): scales flat as the known + // set grows, where a generated switch eventually falls off the inline threshold. KEYOF_NAMES and + // KEYOF_VALUES are parallel; the table places names by hash and a parallel ids[] by slot. + private static final String[] KEYOF_NAMES = { + Tags.ERROR, + DDTags.PARENT_ID, + DDTags.BASE_SERVICE, + Tags.VERSION, + ENV, + DDTags.DJM_ENABLED, + DDTags.DSM_ENABLED, + DDTags.TRACER_HOST, + DDTags.DD_INTEGRATION, + DDTags.DD_SVC_SRC, + Tags.PEER_SERVICE, + DDTags.PEER_SERVICE_REMAPPED_FROM, + Tags.HTTP_METHOD, + Tags.HTTP_ROUTE, + Tags.HTTP_URL, + Tags.PEER_HOSTNAME, + Tags.PEER_HOST_IPV4, + Tags.PEER_HOST_IPV6, + Tags.PEER_PORT, + Tags.COMPONENT, + Tags.SPAN_KIND, + DDTags.LANGUAGE_TAG_KEY, + Tags.DB_TYPE, + Tags.DB_INSTANCE, + Tags.DB_USER, + Tags.DB_OPERATION, + Tags.DB_POOL_NAME, + }; + + private static final long[] KEYOF_VALUES = { + ERROR_ID, + PARENT_ID, + BASE_SERVICE_ID, + VERSION_ID, + ENV_ID, + DJM_ENABLED_ID, + DSM_ENABLED_ID, + TRACER_HOST_ID, + INTEGRATION_ID, + SVC_SRC_ID, + PEER_SERVICE_ID, + PEER_SERVICE_REMAPPED_FROM_ID, + HTTP_METHOD_ID, + HTTP_ROUTE_ID, + HTTP_URL_ID, + PEER_HOSTNAME_ID, + PEER_HOST_IPV4_ID, + PEER_HOST_IPV6_ID, + PEER_PORT_ID, + COMPONENT_ID, + SPAN_KIND_ID, + LANGUAGE_ID, + DB_TYPE_ID, + DB_INSTANCE_ID, + DB_USER_ID, + DB_OPERATION_ID, + DB_POOL_NAME_ID, + }; + + // Static-final raw arrays placed by StringIndex.Support: the JIT folds these refs to constants on + // the keyOf hot path (the fastest of StringIndex's three usage modes — no instance dereference). + private static final int[] KEYOF_HASHES; + private static final String[] KEYOF_KEYS; + private static final long[] KEYOF_IDS; + + static { + StringIndex.Data data = StringIndex.Support.create(KEYOF_NAMES); + long[] ids = new long[data.names.length]; + for (int j = 0; j < KEYOF_NAMES.length; j++) { + ids[StringIndex.Support.indexOf(data.hashes, data.names, KEYOF_NAMES[j])] = KEYOF_VALUES[j]; + } + KEYOF_HASHES = data.hashes; + KEYOF_KEYS = data.names; + KEYOF_IDS = ids; + } + + static final KnownTagCodec.Resolver RESOLVER = + new KnownTagCodec.Resolver() { + @Override + public String nameOf(long tagId) { + switch (KnownTagCodec.globalSerial(tagId)) { + case ERROR_SERIAL: + return Tags.ERROR; + case PARENT_ID_SERIAL: + return DDTags.PARENT_ID; + case BASE_SERVICE_SERIAL: + return DDTags.BASE_SERVICE; + case VERSION_SERIAL: + return Tags.VERSION; + case ENV_SERIAL: + return ENV; + case DJM_ENABLED_SERIAL: + return DDTags.DJM_ENABLED; + case DSM_ENABLED_SERIAL: + return DDTags.DSM_ENABLED; + case TRACER_HOST_SERIAL: + return DDTags.TRACER_HOST; + case INTEGRATION_SERIAL: + return DDTags.DD_INTEGRATION; + case SVC_SRC_SERIAL: + return DDTags.DD_SVC_SRC; + case PEER_SERVICE_SERIAL: + return Tags.PEER_SERVICE; + case PEER_SERVICE_REMAPPED_FROM_SERIAL: + return DDTags.PEER_SERVICE_REMAPPED_FROM; + case HTTP_METHOD_SERIAL: + return Tags.HTTP_METHOD; + case HTTP_ROUTE_SERIAL: + return Tags.HTTP_ROUTE; + case HTTP_URL_SERIAL: + return Tags.HTTP_URL; + case PEER_HOSTNAME_SERIAL: + return Tags.PEER_HOSTNAME; + case PEER_HOST_IPV4_SERIAL: + return Tags.PEER_HOST_IPV4; + case PEER_HOST_IPV6_SERIAL: + return Tags.PEER_HOST_IPV6; + case PEER_PORT_SERIAL: + return Tags.PEER_PORT; + case COMPONENT_SERIAL: + return Tags.COMPONENT; + case SPAN_KIND_SERIAL: + return Tags.SPAN_KIND; + case LANGUAGE_SERIAL: + return DDTags.LANGUAGE_TAG_KEY; + case DB_TYPE_SERIAL: + return Tags.DB_TYPE; + case DB_INSTANCE_SERIAL: + return Tags.DB_INSTANCE; + case DB_USER_SERIAL: + return Tags.DB_USER; + case DB_OPERATION_SERIAL: + return Tags.DB_OPERATION; + case DB_POOL_NAME_SERIAL: + return Tags.DB_POOL_NAME; + default: + return null; + } + } + + @Override + public int slotCount() { + return SLOT_COUNT; + } + + @Override + public long keyOf(String name) { + int slot = StringIndex.Support.indexOf(KEYOF_HASHES, KEYOF_KEYS, name); + return slot < 0 ? 0L : KEYOF_IDS[slot]; + } + }; + + static { + KnownTagCodec.register(RESOLVER); + } + + /** + * Forces resolver registration. Merely invoking this static method runs {@code } (which + * registers {@link #RESOLVER}), so calling it once at tracer init flips the dense store live; + * idempotent. Until something references this class the registry stays dormant and {@code keyOf} + * returns 0, so tag storage is byte-identical to the bucket-only behavior. + */ + public static void init() {} + + private KnownTags() {} +} diff --git a/internal-api/src/main/java/datadog/trace/api/TagMap.java b/internal-api/src/main/java/datadog/trace/api/TagMap.java index cdf68653c11..e2a26744758 100644 --- a/internal-api/src/main/java/datadog/trace/api/TagMap.java +++ b/internal-api/src/main/java/datadog/trace/api/TagMap.java @@ -47,10 +47,9 @@ */ public final class TagMap implements Map, Iterable { /** Immutable empty TagMap - similar to {@link Collections#emptyMap()} */ - // Frozen view over a length-1 array: bucket masking needs a power-of-two array length (size 0 - // would fail with ArrayIndexOutOfBoundsException, size 1 works), and the private constructor - // reads no statics, so this is safe to build directly during TagMap's . - public static final TagMap EMPTY = new TagMap(new Object[1], 0); + // Frozen view over a power-of-two array; the private constructor reads no statics, so this is + // safe to build directly during TagMap's . + public static final TagMap EMPTY = new TagMap(new Object[1 << 4], 0); /** Creates a new mutable TagMap that contains the contents of map */ public static final TagMap fromMap(Map map) { @@ -1005,10 +1004,43 @@ public EntryChange next() { * removed from the collision chain. */ - private final Object[] buckets; + // Shared immutable empty buckets (all null, length 16). Every map points here until its first + // custom-tag write copies-on-write to a private array (materializeBuckets), so an all-known / + // known-heavy map (e.g. the trace-tier read-through parent) allocates ZERO buckets. Length is + // always 16, so reads need no null guard and read-through bucket alignment (hash & 15) holds. + private static final Object[] EMPTY_BUCKETS = new Object[1 << 4]; + + private Object[] buckets; private int size; private boolean frozen; + /** + * Dense known-tag store (dense-tagmap-design §5). Values for KNOWN tags (those {@link + * KnownTagCodec#keyOf} resolves to a stored id) live in these INSERTION-ORDERED parallel arrays + * with NO per-tag {@link Entry} object — the allocation win. Lazily allocated on the first + * known-tag write ({@code null} until then, so all-unknown maps pay nothing) and grown x2 from + * {@link #KNOWN_INIT_CAP}. Matched by globalSerial via a linear scan ({@link #knownIndexOf}); + * reads aren't hot, so O(knownCount) is fine and positional indexing is deferred. Dormant until a + * resolver is registered: {@code keyOf} returns 0, so nothing routes here and production is + * byte-identical. + * + *

Disjoint from {@link #buckets} by construction: known-ness is global ({@code keyOf} is + * deterministic), so a known tag is ALWAYS dense and never bucketed, and vice-versa. That + * disjointness keeps read-through shadow checks within-region — a parent dense entry can only be + * shadowed by a local dense entry of the same id, a parent bucket entry only by a local bucket + * entry — so the existing bucket read-through code is unchanged. + * + *

{@link #size} counts bucket entries only; {@link #knownCount} counts dense entries; the + * local total is {@code size + knownCount}. + */ + private long[] knownIds; + + private Object[] knownValues; + private int knownCount; + + private static final int KNOWN_INIT_CAP = + 12; // generous per-type max stopgap; exact per-type sizing comes with the tag registry + /** * Optional frozen parent for read-through (level-split phase 1). When non-null, reads that miss * the local buckets fall through to the parent; a local entry shadows the parent's (local-wins). @@ -1038,8 +1070,9 @@ public TagMap() { * can treat it as fixed. */ private TagMap(TagMap parent) { - // needs to be a power of 2 for bucket masking calculation to work as intended - this.buckets = new Object[1 << 4]; + // Start on the shared empty buckets; materializeBuckets() COWs to a private power-of-two array + // on the first custom-tag write. All-known maps never allocate buckets. + this.buckets = EMPTY_BUCKETS; this.size = 0; this.frozen = false; this.parent = parent; @@ -1060,17 +1093,24 @@ public boolean isOptimized() { @Override public int size() { // Exact (Map contract). Under read-through resolves the union; prefer estimateSize() for hints. + int local = this.size + this.knownCount; // buckets + dense TagMap parent = this.parent; - return parent == null ? this.size : this.size + this.visibleParentCount(); + return parent == null ? local : local + this.visibleParentCount(); } /** * Exact count of parent entries not shadowed locally or tombstoned (the read-through addition). */ private int visibleParentCount() { + int count = 0; + // parent dense entries not shadowed by a local dense entry / tombstoned + long[] parentIds = this.parent.knownIds; + int parentKnownCount = this.parent.knownCount; + for (int i = 0; i < parentKnownCount; ++i) { + if (!this.parentDenseHidden(parentIds[i])) count++; + } Object[] parentBuckets = this.parent.buckets; Object[] thisBuckets = this.buckets; - int count = 0; for (int i = 0; i < parentBuckets.length; ++i) { Object parentBucket = parentBuckets[i]; Object localBucket = thisBuckets[i]; @@ -1094,7 +1134,7 @@ private int visibleParentCount() { @Override public boolean isEmpty() { // Exact (Map contract). Under read-through resolves the parent; prefer isDefinitelyEmpty(). - if (this.size != 0) { + if (this.size != 0 || this.knownCount != 0) { return false; } TagMap parent = this.parent; @@ -1110,12 +1150,15 @@ public boolean isEmpty() { } public boolean isDefinitelyEmpty() { - return this.size == 0 && (this.parent == null || this.parent.isDefinitelyEmpty()); + return this.size == 0 + && this.knownCount == 0 + && (this.parent == null || this.parent.isDefinitelyEmpty()); } public int estimateSize() { - // Upper bound: local + parent, ignoring read-through shadowing/removals (over-counts). - return this.parent == null ? this.size : this.size + this.parent.estimateSize(); + // Upper bound: local (buckets + dense) + parent, ignoring shadowing/removals (over-counts). + int local = this.size + this.knownCount; + return this.parent == null ? local : local + this.parent.estimateSize(); } @Deprecated @@ -1241,8 +1284,15 @@ public Entry getEntry(String tag) { return parent.getEntry(tag); } - /** Looks up an entry in this map's own buckets only — no read-through to the parent. */ + /** Looks up an entry in this map's own storage only (dense then buckets) — no read-through. */ private Entry getLocalEntry(String tag) { + // Known tags live in the dense store; resolve identity and check there first. keyOf is a no-op + // (returns 0 -> isStored false) until a resolver is registered, so this is inert in production. + long id = KnownTagCodec.keyOf(tag); + if (KnownTagCodec.isStored(id)) { + Object known = this.knownRawValue(id); + return known == null ? null : Entry.newAnyEntry(tag, known); + } Object[] thisBuckets = this.buckets; int hash = TagMap.Entry._hash(tag); return findInBucket(thisBuckets[hash & (thisBuckets.length - 1)], hash, tag); @@ -1276,10 +1326,94 @@ private boolean parentEntryVisibleInBucket(Object localBucket, Entry parentEntry == null; // not shadowed by a local entry } + // ---- dense known-tag store (see the knownIds field doc) + // ---------------------------------------- + + /** + * Linear scan of the dense store for {@code tagId}, returning its index or -1. Ids are canonical + * (the only way one enters is {@link KnownTagCodec#keyOf} or a {@code KnownTags} constant, both + * canonical), so a full {@code long} compare is exact and cheaper than extracting globalSerial. + */ + private int knownIndexOf(long tagId) { + long[] ids = this.knownIds; + int n = this.knownCount; + for (int i = 0; i < n; ++i) { + if (ids[i] == tagId) return i; + } + return -1; + } + + private void ensureKnownCapacity() { + if (this.knownIds == null) { + this.knownIds = new long[KNOWN_INIT_CAP]; + this.knownValues = new Object[KNOWN_INIT_CAP]; + } else if (this.knownCount == this.knownIds.length) { + int newCap = this.knownIds.length << 1; + this.knownIds = Arrays.copyOf(this.knownIds, newCap); + this.knownValues = Arrays.copyOf(this.knownValues, newCap); + } + } + + /** + * Stores a known tag's value densely (no {@link Entry} alloc). Overwrites in place when present + * (returning the prior value materialized as an Entry, per the {@code Map} contract — usually + * discarded by {@code set}); otherwise appends, growing x2 as needed. + */ + private Entry putKnownValue(long tagId, Object value) { + int i = this.knownIndexOf(tagId); + if (i >= 0) { + Object prior = this.knownValues[i]; + this.knownValues[i] = value; + return materializeKnown(tagId, prior); + } + this.ensureKnownCapacity(); + int slot = this.knownCount++; + this.knownIds[slot] = tagId; + this.knownValues[slot] = value; + return null; + } + + /** Raw dense value for {@code tagId}, or {@code null} when absent (no Entry, no boxing). */ + private Object knownRawValue(long tagId) { + int i = this.knownIndexOf(tagId); + return i < 0 ? null : this.knownValues[i]; + } + + /** + * Removes a known tag from the dense store (swap-with-last), returning the prior Entry or null. + */ + private Entry removeKnown(long tagId) { + int i = this.knownIndexOf(tagId); + if (i < 0) return null; + Object prior = this.knownValues[i]; + int last = --this.knownCount; + this.knownIds[i] = this.knownIds[last]; + this.knownValues[i] = this.knownValues[last]; + this.knownIds[last] = 0L; + this.knownValues[last] = null; + return materializeKnown(tagId, prior); + } + + /** Materializes a transient Entry for a dense (id, value) pair — only on explicit get/iterate. */ + private static Entry materializeKnown(long tagId, Object value) { + return Entry.newAnyEntry(KnownTagCodec.nameOf(tagId), value); + } + + /** + * Whether a parent dense entry is hidden through this child: shadowed by a local dense entry of + * the same id, or tombstoned. (Disjointness means a parent dense entry can't be shadowed by a + * local bucket entry — known tags never bucket — so no bucket check is needed here.) + */ + private boolean parentDenseHidden(long tagId) { + if (this.knownIndexOf(tagId) >= 0) return true; // shadowed by a local dense entry + return this.removedFromParent != null + && this.removedFromParent.contains(KnownTagCodec.nameOf(tagId)); // tombstoned + } + @Deprecated @Override public Object put(String tag, Object value) { - TagMap.Entry entry = this.getAndSet(Entry.newAnyEntry(tag, value)); + TagMap.Entry entry = this.getAndSet(tag, value); return entry == null ? null : entry.objectValue(); } @@ -1290,39 +1424,75 @@ public void set(TagMap.EntryReader newEntryReader) { this.getAndSet(newEntryReader.entry()); } + // The set(String, ...) family delegates to the matching getAndSet(String, ...) overload, which + // routes known tags to the dense store BEFORE constructing any Entry (so a known-tag set + // allocates no Entry). The discarded return is free on the common first-set path (prior == null). public void set(String tag, Object value) { - this.getAndSet(Entry.newAnyEntry(tag, value)); + this.getAndSet(tag, value); } public void set(String tag, CharSequence value) { - this.getAndSet(Entry.newObjectEntry(tag, value)); + this.getAndSet(tag, value); } public void set(String tag, boolean value) { - this.getAndSet(Entry.newBooleanEntry(tag, value)); + this.getAndSet(tag, value); } public void set(String tag, int value) { - this.getAndSet(Entry.newIntEntry(tag, value)); + this.getAndSet(tag, value); } public void set(String tag, long value) { - this.getAndSet(Entry.newLongEntry(tag, value)); + this.getAndSet(tag, value); } public void set(String tag, float value) { - this.getAndSet(Entry.newFloatEntry(tag, value)); + this.getAndSet(tag, value); } public void set(String tag, double value) { - this.getAndSet(Entry.newDoubleEntry(tag, value)); + this.getAndSet(tag, value); } public Entry getAndSet(Entry newEntry) { if (newEntry == null) { return null; } + // Entry-based path (set(EntryReader), entry-sharing). The Entry is already constructed by the + // caller, so a known tag keeps its value densely and drops the Entry. The hot string/typed + // setters route to dense BEFORE constructing an Entry (see set/getAndSet(String, ...)) so a + // known-tag set allocates no Entry at all. + long id = KnownTagCodec.keyOf(newEntry.tag); + return KnownTagCodec.isStored(id) + ? this.getAndSetKnown(id, newEntry.tag, newEntry.objectValue()) + : this.getAndSetBucket(newEntry); + } + + /** + * Stores a known tag's (resolved id, value) densely with NO Entry retained — the alloc win. + * Returns the prior value materialized as an Entry (Map contract); {@code set} discards it. + */ + private Entry getAndSetKnown(long id, String tag, Object value) { + this.checkWriteAccess(); + if (this.removedFromParent != null) { + this.removedFromParent.remove(tag); + } + return this.putKnownValue(id, value); + } + + /** Copy-on-write the shared empty buckets to a private array on the first bucket write. */ + private Object[] materializeBuckets() { + Object[] b = this.buckets; + if (b == EMPTY_BUCKETS) { + b = new Object[1 << 4]; + this.buckets = b; + } + return b; + } + /** Stores an entry in the hash buckets — the unknown/custom-tag path. */ + private Entry getAndSetBucket(Entry newEntry) { this.checkWriteAccess(); // Re-setting a key clears any read-through tombstone for it (the new value overrides the @@ -1331,7 +1501,7 @@ public Entry getAndSet(Entry newEntry) { this.removedFromParent.remove(newEntry.tag); } - Object[] thisBuckets = this.buckets; + Object[] thisBuckets = this.materializeBuckets(); int newHash = newEntry.hash(); int bucketIndex = newHash & (thisBuckets.length - 1); @@ -1376,32 +1546,56 @@ public Entry getAndSet(Entry newEntry) { return null; } + // Each getAndSet(String, ...) resolves keyOf FIRST: a known tag stores its value densely with no + // Entry (boxing the primitive only on this branch); a custom tag falls back to the typed Entry + // (no boxing for primitives, preserving the bucket store's no-box property). public Entry getAndSet(String tag, Object value) { - return this.getAndSet(Entry.newAnyEntry(tag, value)); + long id = KnownTagCodec.keyOf(tag); + return KnownTagCodec.isStored(id) + ? this.getAndSetKnown(id, tag, value) + : this.getAndSetBucket(Entry.newAnyEntry(tag, value)); } public Entry getAndSet(String tag, CharSequence value) { - return this.getAndSet(Entry.newObjectEntry(tag, value)); + long id = KnownTagCodec.keyOf(tag); + return KnownTagCodec.isStored(id) + ? this.getAndSetKnown(id, tag, value) + : this.getAndSetBucket(Entry.newObjectEntry(tag, value)); } public TagMap.Entry getAndSet(String tag, boolean value) { - return this.getAndSet(Entry.newBooleanEntry(tag, value)); + long id = KnownTagCodec.keyOf(tag); + return KnownTagCodec.isStored(id) + ? this.getAndSetKnown(id, tag, Boolean.valueOf(value)) + : this.getAndSetBucket(Entry.newBooleanEntry(tag, value)); } public TagMap.Entry getAndSet(String tag, int value) { - return this.getAndSet(Entry.newIntEntry(tag, value)); + long id = KnownTagCodec.keyOf(tag); + return KnownTagCodec.isStored(id) + ? this.getAndSetKnown(id, tag, Integer.valueOf(value)) + : this.getAndSetBucket(Entry.newIntEntry(tag, value)); } public TagMap.Entry getAndSet(String tag, long value) { - return this.getAndSet(Entry.newLongEntry(tag, value)); + long id = KnownTagCodec.keyOf(tag); + return KnownTagCodec.isStored(id) + ? this.getAndSetKnown(id, tag, Long.valueOf(value)) + : this.getAndSetBucket(Entry.newLongEntry(tag, value)); } public TagMap.Entry getAndSet(String tag, float value) { - return this.getAndSet(Entry.newFloatEntry(tag, value)); + long id = KnownTagCodec.keyOf(tag); + return KnownTagCodec.isStored(id) + ? this.getAndSetKnown(id, tag, Float.valueOf(value)) + : this.getAndSetBucket(Entry.newFloatEntry(tag, value)); } public TagMap.Entry getAndSet(String tag, double value) { - return this.getAndSet(Entry.newDoubleEntry(tag, value)); + long id = KnownTagCodec.keyOf(tag); + return KnownTagCodec.isStored(id) + ? this.getAndSetKnown(id, tag, Double.valueOf(value)) + : this.getAndSetBucket(Entry.newDoubleEntry(tag, value)); } public void putAll(Map map) { @@ -1435,7 +1629,9 @@ public void putAll(TagMap that) { } private void putAllOptimizedMap(TagMap that) { - if (this.size == 0) { + // "empty" must consider BOTH local regions — a map with only dense entries has size == 0 but is + // not empty, and putAllIntoEmptyMap would clobber its dense store. + if (this.size == 0 && this.knownCount == 0) { this.putAllIntoEmptyMap(that); } else { this.putAllMerge(that); @@ -1443,7 +1639,9 @@ private void putAllOptimizedMap(TagMap that) { } private void putAllMerge(TagMap that) { - Object[] thisBuckets = this.buckets; + // COW our buckets only if the source has bucket entries to merge in; otherwise the loop below + // writes nothing and the shared empty buckets stay shared. + Object[] thisBuckets = (that.size > 0) ? this.materializeBuckets() : this.buckets; Object[] thatBuckets = that.buckets; // Since TagMap-s don't support expansion, buckets are perfectly aligned @@ -1554,33 +1752,49 @@ private void putAllMerge(TagMap that) { } } } + + // merge the source's dense known-tag entries; incoming clobbers existing (same as buckets) + for (int i = 0; i < that.knownCount; ++i) { + this.putKnownValue(that.knownIds[i], that.knownValues[i]); + } } /* * Specially optimized version of putAll for the common case of destination map being empty */ private void putAllIntoEmptyMap(TagMap that) { - Object[] thisBuckets = this.buckets; - Object[] thatBuckets = that.buckets; - - // Check against both thisBuckets.length && thatBuckets.length is to help the JIT do bound check - // elimination - for (int i = 0; i < thisBuckets.length && i < thatBuckets.length; ++i) { - Object thatBucket = thatBuckets[i]; - - // faster to explicitly null check first, then do instanceof - if (thatBucket == null) { - // do nothing - } else if (thatBucket instanceof BucketGroup) { - // if it is a BucketGroup, then need to clone - BucketGroup thatGroup = (BucketGroup) thatBucket; + // Only copy buckets (and COW ours) when the source actually has bucket entries; an all-known + // source leaves us on the shared empty buckets. + if (that.size > 0) { + Object[] thisBuckets = this.materializeBuckets(); + Object[] thatBuckets = that.buckets; + + // Check against both thisBuckets.length && thatBuckets.length is to help the JIT do bound + // check elimination + for (int i = 0; i < thisBuckets.length && i < thatBuckets.length; ++i) { + Object thatBucket = thatBuckets[i]; + + // faster to explicitly null check first, then do instanceof + if (thatBucket == null) { + // do nothing + } else if (thatBucket instanceof BucketGroup) { + // if it is a BucketGroup, then need to clone + BucketGroup thatGroup = (BucketGroup) thatBucket; - thisBuckets[i] = thatGroup.cloneChain(); - } else { // if ( thatBucket instanceof Entry ) - thisBuckets[i] = thatBucket; + thisBuckets[i] = thatGroup.cloneChain(); + } else { // if ( thatBucket instanceof Entry ) + thisBuckets[i] = thatBucket; + } } + this.size = that.size; + } + + // clone the dense known-tag store (values are immutable boxes/objects -> safe to share refs) + if (that.knownCount > 0) { + this.knownIds = Arrays.copyOf(that.knownIds, that.knownIds.length); + this.knownValues = Arrays.copyOf(that.knownValues, that.knownValues.length); + this.knownCount = that.knownCount; } - this.size = that.size; } public void fillMap(Map map) { @@ -1599,6 +1813,9 @@ public void fillMap(Map map) { thisGroup.fillMapFromChain(map); } } + for (int i = 0; i < this.knownCount; ++i) { + map.put(KnownTagCodec.nameOf(this.knownIds[i]), this.knownValues[i]); + } } public void fillStringMap(Map stringMap) { @@ -1617,6 +1834,11 @@ public void fillStringMap(Map stringMap) { thisGroup.fillStringMapFromChain(stringMap); } } + for (int i = 0; i < this.knownCount; ++i) { + stringMap.put( + KnownTagCodec.nameOf(this.knownIds[i]), + TagValueConversions.toString(this.knownValues[i])); + } } @Override @@ -1658,8 +1880,13 @@ public Entry getAndRemove(String tag) { return localRemoved; } - /** Removes an entry from this map's own buckets only — no parent/tombstone handling. */ + /** Removes an entry from this map's own storage only — no parent/tombstone handling. */ private Entry removeLocal(String tag) { + long id = KnownTagCodec.keyOf(tag); + if (KnownTagCodec.isStored(id)) { + return this.removeKnown(id); + } + Object[] thisBuckets = this.buckets; int hash = TagMap.Entry._hash(tag); @@ -1727,6 +1954,15 @@ public Stream stream() { @Override public void forEach(Consumer consumer) { + // local dense known tags via a reused flyweight (no per-entry Entry alloc — the serialize win) + if (this.knownCount > 0) { + EntryReadingHelper reader = new EntryReadingHelper(); + for (int i = 0; i < this.knownCount; ++i) { + reader.set(KnownTagCodec.nameOf(this.knownIds[i]), this.knownValues[i]); + consumer.accept(reader); + } + } + Object[] thisBuckets = this.buckets; for (int i = 0; i < thisBuckets.length; ++i) { @@ -1751,6 +1987,21 @@ public void forEach(Consumer consumer) { } private void forEachParent(Consumer consumer) { + // parent dense known tags not shadowed by a local dense entry / tombstoned + long[] parentIds = this.parent.knownIds; + int parentKnownCount = this.parent.knownCount; + if (parentKnownCount > 0) { + Object[] parentValues = this.parent.knownValues; + EntryReadingHelper reader = new EntryReadingHelper(); + for (int i = 0; i < parentKnownCount; ++i) { + long id = parentIds[i]; + if (!this.parentDenseHidden(id)) { + reader.set(KnownTagCodec.nameOf(id), parentValues[i]); + consumer.accept(reader); + } + } + } + Object[] localBuckets = this.buckets; Object[] parentBuckets = this.parent.buckets; // leaf parent: same length, same bucket per key for (int i = 0; i < parentBuckets.length; ++i) { @@ -1774,6 +2025,14 @@ private void forEachParent(Consumer consumer) { } public void forEach(T thisObj, BiConsumer consumer) { + if (this.knownCount > 0) { + EntryReadingHelper reader = new EntryReadingHelper(); + for (int i = 0; i < this.knownCount; ++i) { + reader.set(KnownTagCodec.nameOf(this.knownIds[i]), this.knownValues[i]); + consumer.accept(thisObj, reader); + } + } + Object[] thisBuckets = this.buckets; for (int i = 0; i < thisBuckets.length; ++i) { @@ -1797,6 +2056,20 @@ public void forEach(T thisObj, BiConsumer con } private void forEachParent(T thisObj, BiConsumer consumer) { + long[] parentIds = this.parent.knownIds; + int parentKnownCount = this.parent.knownCount; + if (parentKnownCount > 0) { + Object[] parentValues = this.parent.knownValues; + EntryReadingHelper reader = new EntryReadingHelper(); + for (int i = 0; i < parentKnownCount; ++i) { + long id = parentIds[i]; + if (!this.parentDenseHidden(id)) { + reader.set(KnownTagCodec.nameOf(id), parentValues[i]); + consumer.accept(thisObj, reader); + } + } + } + Object[] localBuckets = this.buckets; Object[] parentBuckets = this.parent.buckets; // leaf parent: same length, same bucket per key for (int i = 0; i < parentBuckets.length; ++i) { @@ -1823,6 +2096,14 @@ private void forEachParent(T thisObj, BiConsumer void forEach( T thisObj, U otherObj, TriConsumer consumer) { + if (this.knownCount > 0) { + EntryReadingHelper reader = new EntryReadingHelper(); + for (int i = 0; i < this.knownCount; ++i) { + reader.set(KnownTagCodec.nameOf(this.knownIds[i]), this.knownValues[i]); + consumer.accept(thisObj, otherObj, reader); + } + } + Object[] thisBuckets = this.buckets; for (int i = 0; i < thisBuckets.length; ++i) { @@ -1847,6 +2128,20 @@ public void forEach( private void forEachParent( T thisObj, U otherObj, TriConsumer consumer) { + long[] parentIds = this.parent.knownIds; + int parentKnownCount = this.parent.knownCount; + if (parentKnownCount > 0) { + Object[] parentValues = this.parent.knownValues; + EntryReadingHelper reader = new EntryReadingHelper(); + for (int i = 0; i < parentKnownCount; ++i) { + long id = parentIds[i]; + if (!this.parentDenseHidden(id)) { + reader.set(KnownTagCodec.nameOf(id), parentValues[i]); + consumer.accept(thisObj, otherObj, reader); + } + } + } + Object[] localBuckets = this.buckets; Object[] parentBuckets = this.parent.buckets; // leaf parent: same length, same bucket per key for (int i = 0; i < parentBuckets.length; ++i) { @@ -1874,8 +2169,12 @@ private void forEachParent( public void clear() { this.checkWriteAccess(); - Arrays.fill(this.buckets, null); + // Drop the private bucket array back to the shared empty sentinel (also avoids mutating it). + this.buckets = EMPTY_BUCKETS; this.size = 0; + this.knownIds = null; + this.knownValues = null; + this.knownCount = 0; } public TagMap freeze() { @@ -1930,6 +2229,20 @@ void checkIntegrity() { } } + // dense store: ids must be unique (no tag stored twice) and the count within array bounds. + if (this.knownCount > 0) { + if (this.knownIds == null || this.knownCount > this.knownIds.length) { + throw new IllegalStateException("incorrect known count"); + } + for (int i = 0; i < this.knownCount; ++i) { + for (int j = i + 1; j < this.knownCount; ++j) { + if (this.knownIds[i] == this.knownIds[j]) { + throw new IllegalStateException("duplicate known id"); + } + } + } + } + if (this.size != this.computeSize()) { throw new IllegalStateException("incorrect size"); } @@ -2061,13 +2374,23 @@ abstract static class IteratorBase { private Object[] buckets; private boolean inParent = false; - private Entry nextEntry; + // Currency is EntryReader, not Entry: a BUCKET entry is its own (real, retain-safe) Entry, but + // a + // DENSE entry is emitted via the reused denseReader flyweight (alloc-free, "use now"). This is + // the contract of TagMap.iterator()/keySet()/values(). entrySet() (Iterator) sits on + // top and calls .entry() per next() to get a real retain-safe Entry (see EntriesIterator). + private EntryReader nextEntry; + private EntryReadingHelper denseReader; // lazily created on the first dense emit private int bucketIndex = -1; private BucketGroup group = null; private int groupIndex = 0; + // dense-store cursors: local known tags, then (read-through) parent known tags + private int knownIndex = 0; + private int parentKnownIndex = 0; + IteratorBase(TagMap map) { this.map = map; this.localBuckets = map.buckets; @@ -2081,9 +2404,9 @@ public final boolean hasNext() { return this.nextEntry != null; } - final Entry nextEntryOrThrowNoSuchElement() { + final EntryReader nextEntryOrThrowNoSuchElement() { if (this.nextEntry != null) { - Entry nextEntry = this.nextEntry; + EntryReader nextEntry = this.nextEntry; this.nextEntry = null; return nextEntry; } @@ -2095,9 +2418,9 @@ final Entry nextEntryOrThrowNoSuchElement() { } } - final Entry nextEntryOrNull() { + final EntryReader nextEntryOrNull() { if (this.nextEntry != null) { - Entry nextEntry = this.nextEntry; + EntryReader nextEntry = this.nextEntry; this.nextEntry = null; return nextEntry; } @@ -2105,7 +2428,14 @@ final Entry nextEntryOrNull() { return this.hasNext() ? this.nextEntry : null; } - private final Entry advance() { + private final EntryReader advance() { + // phase: local dense known tags (local entries always emit — no shadow check). Emitted via + // the + // reused denseReader flyweight — NO per-entry Entry alloc (the read/serialize alloc win). + if (this.knownIndex < this.map.knownCount) { + int i = this.knownIndex++; + return this.emitDense(this.map.knownIds[i], this.map.knownValues[i]); + } while (true) { Entry tagEntry = this.rawAdvance(); if (tagEntry != null) { @@ -2120,8 +2450,14 @@ private final Entry advance() { continue; // parent entry shadowed/tombstoned -> skip } - // current array exhausted; switch to the parent's buckets once (read-through union) + // current bucket array exhausted; before switching to parent buckets, drain parent dense + // (read-through union). Re-entrant: while inParent stays false, the exhausted local-bucket + // rawAdvance keeps returning null and funnels back here until parent dense is fully + // drained. if (!this.inParent && this.map.parent != null) { + EntryReader parentDense = this.advanceParentDense(); + if (parentDense != null) return parentDense; + this.inParent = true; this.buckets = this.map.parent.buckets; this.bucketIndex = -1; @@ -2133,6 +2469,33 @@ private final Entry advance() { } } + /** + * Next visible parent dense entry (not shadowed locally / tombstoned), or null when drained. + */ + private final EntryReader advanceParentDense() { + TagMap p = this.map.parent; + long[] parentIds = p.knownIds; + int parentKnownCount = p.knownCount; + while (this.parentKnownIndex < parentKnownCount) { + int i = this.parentKnownIndex++; + long id = parentIds[i]; + if (!this.map.parentDenseHidden(id)) { + return this.emitDense(id, p.knownValues[i]); + } + } + return null; + } + + /** Sets and returns the reused dense flyweight (lazily created); "use now", do not retain. */ + private EntryReader emitDense(long tagId, Object value) { + EntryReadingHelper reader = this.denseReader; + if (reader == null) { + reader = this.denseReader = new EntryReadingHelper(); + } + reader.set(KnownTagCodec.nameOf(tagId), value); + return reader; + } + /** Next raw entry in the current bucket array, ignoring shadowing/tombstones. */ private final Entry rawAdvance() { while (this.bucketIndex < this.buckets.length) { @@ -2662,9 +3025,26 @@ public boolean isEmpty() { @Override public Iterator> iterator() { - @SuppressWarnings({"rawtypes", "unchecked"}) - Iterator> iter = (Iterator) this.map.iterator(); - return iter; + return new EntriesIterator(this.map); + } + } + + /** + * entrySet() yields real, retain-safe {@code Map.Entry} objects. It sits on top of the + * EntryReader iterator and materializes each via {@code .entry()}: a bucket entry's reader IS the + * real stored Entry (returns {@code this}, free); a dense entry's flyweight materializes a fresh + * Entry. Deliberately NOT alloc-optimized for dense — bulk reads use {@code forEach}/EntryReader, + * and manual instrumentation does point get/set, not bulk entrySet iteration. + */ + static final class EntriesIterator extends IteratorBase + implements Iterator> { + EntriesIterator(TagMap map) { + super(map); + } + + @Override + public Map.Entry next() { + return this.nextEntryOrThrowNoSuchElement().entry(); } } diff --git a/internal-api/src/test/java/datadog/trace/api/KnownTagsTest.java b/internal-api/src/test/java/datadog/trace/api/KnownTagsTest.java new file mode 100644 index 00000000000..11d01bc7ec8 --- /dev/null +++ b/internal-api/src/test/java/datadog/trace/api/KnownTagsTest.java @@ -0,0 +1,152 @@ +package datadog.trace.api; + +import static org.junit.jupiter.api.Assertions.assertEquals; +import static org.junit.jupiter.api.Assertions.assertFalse; +import static org.junit.jupiter.api.Assertions.assertNull; +import static org.junit.jupiter.api.Assertions.assertTrue; + +import datadog.trace.bootstrap.instrumentation.api.Tags; +import java.util.ArrayList; +import java.util.HashSet; +import java.util.List; +import java.util.Set; +import java.util.stream.Stream; +import org.junit.jupiter.api.Test; +import org.junit.jupiter.params.ParameterizedTest; +import org.junit.jupiter.params.provider.Arguments; +import org.junit.jupiter.params.provider.MethodSource; + +/** + * Parity test for the keyOf substrate (slice 1): the {@link KnownTags} registry + the {@link + * KnownTagCodec.Resolver} it registers. Verifies name ↔ id resolution without any dense store + * — {@code keyOf}/{@code nameOf} depend only on globalSerial + name, not on the (dormant) + * positional layout. + */ +class KnownTagsTest { + + /** (name, id) pairs — the full registry. keyOf returns the id verbatim (incl. INTERCEPTED). */ + static Stream knownTags() { + return Stream.of( + Arguments.of(Tags.ERROR, KnownTags.ERROR_ID), + Arguments.of(DDTags.PARENT_ID, KnownTags.PARENT_ID), + Arguments.of(DDTags.BASE_SERVICE, KnownTags.BASE_SERVICE_ID), + Arguments.of(Tags.VERSION, KnownTags.VERSION_ID), + Arguments.of(KnownTags.ENV, KnownTags.ENV_ID), + Arguments.of(DDTags.DJM_ENABLED, KnownTags.DJM_ENABLED_ID), + Arguments.of(DDTags.DSM_ENABLED, KnownTags.DSM_ENABLED_ID), + Arguments.of(DDTags.TRACER_HOST, KnownTags.TRACER_HOST_ID), + Arguments.of(DDTags.DD_INTEGRATION, KnownTags.INTEGRATION_ID), + Arguments.of(DDTags.DD_SVC_SRC, KnownTags.SVC_SRC_ID), + Arguments.of(Tags.PEER_SERVICE, KnownTags.PEER_SERVICE_ID), + Arguments.of(DDTags.PEER_SERVICE_REMAPPED_FROM, KnownTags.PEER_SERVICE_REMAPPED_FROM_ID), + Arguments.of(Tags.HTTP_METHOD, KnownTags.HTTP_METHOD_ID), + Arguments.of(Tags.HTTP_ROUTE, KnownTags.HTTP_ROUTE_ID), + Arguments.of(Tags.HTTP_URL, KnownTags.HTTP_URL_ID), + Arguments.of(Tags.PEER_HOSTNAME, KnownTags.PEER_HOSTNAME_ID), + Arguments.of(Tags.PEER_HOST_IPV4, KnownTags.PEER_HOST_IPV4_ID), + Arguments.of(Tags.PEER_HOST_IPV6, KnownTags.PEER_HOST_IPV6_ID), + Arguments.of(Tags.PEER_PORT, KnownTags.PEER_PORT_ID), + Arguments.of(Tags.COMPONENT, KnownTags.COMPONENT_ID), + Arguments.of(Tags.SPAN_KIND, KnownTags.SPAN_KIND_ID), + Arguments.of(DDTags.LANGUAGE_TAG_KEY, KnownTags.LANGUAGE_ID), + Arguments.of(Tags.DB_TYPE, KnownTags.DB_TYPE_ID), + Arguments.of(Tags.DB_INSTANCE, KnownTags.DB_INSTANCE_ID), + Arguments.of(Tags.DB_USER, KnownTags.DB_USER_ID), + Arguments.of(Tags.DB_OPERATION, KnownTags.DB_OPERATION_ID), + Arguments.of(Tags.DB_POOL_NAME, KnownTags.DB_POOL_NAME_ID)); + } + + /** + * The subset flagged INTERCEPTED (sign bit) — must agree with the interceptor's needsIntercept. + */ + static Stream interceptedTags() { + return Stream.of( + Arguments.of(KnownTags.ERROR_ID), + Arguments.of(KnownTags.PEER_SERVICE_ID), + Arguments.of(KnownTags.HTTP_METHOD_ID), + Arguments.of(KnownTags.HTTP_URL_ID), + Arguments.of(KnownTags.SPAN_KIND_ID)); + } + + @Test + void resolverIsActiveOnceReferenced() { + // referencing any constant triggers KnownTags. -> KnownTagCodec.register + assertTrue(KnownTags.ERROR_ID != 0L); + assertTrue(KnownTagCodec.isActive()); + assertEquals(KnownTags.SLOT_COUNT, KnownTagCodec.slotCount()); + } + + @ParameterizedTest + @MethodSource("knownTags") + void keyOfResolvesNameToId(String name, long id) { + assertEquals(id, KnownTagCodec.keyOf(name), "keyOf(" + name + ")"); + } + + @ParameterizedTest + @MethodSource("knownTags") + void nameOfResolvesIdToName(String name, long id) { + assertEquals(name, KnownTagCodec.nameOf(id), "nameOf(" + name + ")"); + } + + @ParameterizedTest + @MethodSource("knownTags") + void nameHashMatchesEntryHash(String name, long id) { + assertEquals( + (int) TagMap.Entry._hash(name), KnownTagCodec.nameHash(id), "nameHash(" + name + ")"); + } + + @ParameterizedTest + @MethodSource("interceptedTags") + void interceptedTagsCarryFlag(long id) { + assertTrue(KnownTagCodec.isIntercepted(id), "isIntercepted"); + } + + @Test + void nonInterceptedTagsDoNotCarryFlag() { + Set intercepted = new HashSet<>(); + interceptedTags().forEach(a -> intercepted.add((Long) a.get()[0])); + knownTags() + .forEach( + a -> { + long id = (Long) a.get()[1]; + if (!intercepted.contains(id)) { + assertFalse(KnownTagCodec.isIntercepted(id), "not intercepted: " + a.get()[0]); + } + }); + } + + @Test + void unknownNamesResolveToZero() { + assertEquals(0L, KnownTagCodec.keyOf("definitely.not.a.known.tag")); + assertEquals(0L, KnownTagCodec.keyOf("http.statuscode")); // close-but-not-listed + assertEquals(0L, KnownTagCodec.keyOf("")); + } + + @Test + void unknownIdsResolveToNullName() { + assertNull(KnownTagCodec.nameOf(0L)); + assertNull(KnownTagCodec.nameOf(KnownTagCodec.tagId(9999, "made.up"))); + } + + @Test + void errorIsReservedTheRestAreStored() { + assertTrue(KnownTagCodec.isReserved(KnownTags.ERROR_ID), "ERROR reserved"); + assertFalse(KnownTagCodec.isStored(KnownTags.ERROR_ID), "ERROR not stored"); + knownTags() + .forEach( + a -> { + long id = (Long) a.get()[1]; + if (id != KnownTags.ERROR_ID) { + assertTrue(KnownTagCodec.isStored(id), "stored: " + a.get()[0]); + assertFalse(KnownTagCodec.isReserved(id), "not reserved: " + a.get()[0]); + } + }); + } + + @Test + void globalSerialsAreUnique() { + List serials = new ArrayList<>(); + knownTags().forEach(a -> serials.add((long) KnownTagCodec.globalSerial((Long) a.get()[1]))); + assertEquals(serials.size(), new HashSet<>(serials).size(), "globalSerials must be unique"); + } +} diff --git a/internal-api/src/test/java/datadog/trace/api/TagMapDenseForkedTest.java b/internal-api/src/test/java/datadog/trace/api/TagMapDenseForkedTest.java new file mode 100644 index 00000000000..a82742c3acd --- /dev/null +++ b/internal-api/src/test/java/datadog/trace/api/TagMapDenseForkedTest.java @@ -0,0 +1,273 @@ +package datadog.trace.api; + +import static org.junit.jupiter.api.Assertions.assertEquals; +import static org.junit.jupiter.api.Assertions.assertFalse; +import static org.junit.jupiter.api.Assertions.assertNull; +import static org.junit.jupiter.api.Assertions.assertTrue; + +import datadog.trace.bootstrap.instrumentation.api.Tags; +import java.util.HashMap; +import java.util.Map; +import org.junit.jupiter.api.BeforeAll; +import org.junit.jupiter.api.Test; + +/** + * Exercises the dense known-tag store with a LIVE resolver. Registration ({@link KnownTagCodec}) is + * a global static with no un-register, so this lives in a {@code ForkedTest} (isolated JVM) to keep + * dense routing from leaking into the bucket-only tests in the shared JVM. The dense store is + * dormant in production (no resolver) — this is where it actually executes. + * + *

Stored tags (globalSerial ≥ {@code FIRST_STORED_SERIAL}) route to the dense store; reserved + * tags (e.g. {@code error}) and arbitrary tags stay in the hash buckets. Behavior must be + * observationally identical to the bucket store. + */ +class TagMapDenseForkedTest { + + // stored (dense-routed) tags + static final String BASE_SERVICE = DDTags.BASE_SERVICE; + static final String COMPONENT = Tags.COMPONENT; + static final String DB_TYPE = Tags.DB_TYPE; + static final String HTTP_METHOD = Tags.HTTP_METHOD; // stored + intercepted + static final String DB_INSTANCE = Tags.DB_INSTANCE; + // arbitrary (bucket-routed) tags + static final String CUSTOM_A = "custom.tag.a"; + static final String CUSTOM_B = "custom.tag.b"; + + @BeforeAll + static void registerResolver() { + // referencing any KnownTags constant triggers its -> KnownTagCodec.register + assertTrue(KnownTags.BASE_SERVICE_ID != 0L); + assertTrue(KnownTagCodec.isActive(), "resolver must be live for the dense store to engage"); + assertTrue( + KnownTagCodec.isStored(KnownTagCodec.keyOf(BASE_SERVICE)), "base_service routes dense"); + assertFalse( + KnownTagCodec.isStored(KnownTagCodec.keyOf(CUSTOM_A)), "custom tag stays in buckets"); + assertFalse( + KnownTagCodec.isStored(KnownTagCodec.keyOf(Tags.ERROR)), "error is reserved, not stored"); + } + + private static TagMap map() { + return (TagMap) TagMap.create(); + } + + @Test + void knownTagRoundTripsThroughDenseStore() { + TagMap map = map(); + map.set(BASE_SERVICE, "billing"); + map.set(COMPONENT, "spring-web"); + + assertEquals("billing", map.getObject(BASE_SERVICE)); + assertEquals("spring-web", map.getString(COMPONENT)); + assertEquals("billing", map.getEntry(BASE_SERVICE).objectValue()); + assertTrue(map.containsKey(BASE_SERVICE)); + assertEquals(2, map.size()); + map.checkIntegrity(); + } + + @Test + void typedKnownValuesRoundTrip() { + TagMap map = map(); + map.set(DB_TYPE, "postgresql"); + map.set(HTTP_METHOD, "GET"); + map.set(Tags.PEER_PORT, 5432); + + assertEquals("postgresql", map.getString(DB_TYPE)); + assertEquals("GET", map.getString(HTTP_METHOD)); + assertEquals(5432, map.getInt(Tags.PEER_PORT)); + assertEquals(3, map.size()); + map.checkIntegrity(); + } + + @Test + void knownAndUnknownCoexist() { + TagMap map = map(); + map.set(BASE_SERVICE, "billing"); // dense + map.set(CUSTOM_A, "alpha"); // bucket + map.set(DB_TYPE, "h2"); // dense + map.set(CUSTOM_B, "beta"); // bucket + + assertEquals("billing", map.getObject(BASE_SERVICE)); + assertEquals("alpha", map.getObject(CUSTOM_A)); + assertEquals("h2", map.getObject(DB_TYPE)); + assertEquals("beta", map.getObject(CUSTOM_B)); + assertEquals(4, map.size()); + assertFalse(map.isEmpty()); + map.checkIntegrity(); + + Map collected = new HashMap<>(); + map.fillMap(collected); + assertEquals(4, collected.size()); + assertEquals("billing", collected.get(BASE_SERVICE)); + assertEquals("alpha", collected.get(CUSTOM_A)); + assertEquals("h2", collected.get(DB_TYPE)); + assertEquals("beta", collected.get(CUSTOM_B)); + } + + @Test + void overwriteKnownReplacesInPlace() { + TagMap map = map(); + map.set(COMPONENT, "first"); + assertEquals("first", map.getObject(COMPONENT)); + map.set(COMPONENT, "second"); + assertEquals("second", map.getObject(COMPONENT)); + assertEquals(1, map.size()); // overwrite, not append + map.checkIntegrity(); + } + + @Test + void removeKnownClearsIt() { + TagMap map = map(); + map.set(BASE_SERVICE, "billing"); + map.set(DB_TYPE, "h2"); + map.set(CUSTOM_A, "alpha"); + assertEquals(3, map.size()); + + TagMap.Entry removed = map.getAndRemove(BASE_SERVICE); + assertEquals("billing", removed.objectValue()); + assertNull(map.getObject(BASE_SERVICE)); + assertEquals("h2", map.getObject(DB_TYPE)); // sibling dense entry intact + assertEquals("alpha", map.getObject(CUSTOM_A)); + assertEquals(2, map.size()); + map.checkIntegrity(); + } + + @Test + void forEachAndIteratorEmitDenseAndBucketEntries() { + TagMap map = map(); + map.set(BASE_SERVICE, "billing"); + map.set(COMPONENT, "web"); + map.set(CUSTOM_A, "alpha"); + + Map viaForEach = new HashMap<>(); + map.forEach(reader -> viaForEach.put(reader.tag(), reader.objectValue())); + assertEquals(3, viaForEach.size()); + assertEquals("billing", viaForEach.get(BASE_SERVICE)); + assertEquals("web", viaForEach.get(COMPONENT)); + assertEquals("alpha", viaForEach.get(CUSTOM_A)); + + Map viaIterator = new HashMap<>(); + for (TagMap.EntryReader reader : map) { + viaIterator.put(reader.tag(), reader.objectValue()); + } + assertEquals(viaForEach, viaIterator); + } + + @Test + void copyPreservesDenseStore() { + TagMap map = map(); + map.set(BASE_SERVICE, "billing"); + map.set(CUSTOM_A, "alpha"); + + TagMap copy = (TagMap) map.copy(); + assertEquals("billing", copy.getObject(BASE_SERVICE)); + assertEquals("alpha", copy.getObject(CUSTOM_A)); + assertEquals(2, copy.size()); + + // independence: mutating the copy doesn't touch the original's dense store + copy.set(BASE_SERVICE, "shipping"); + assertEquals("shipping", copy.getObject(BASE_SERVICE)); + assertEquals("billing", map.getObject(BASE_SERVICE)); + copy.checkIntegrity(); + map.checkIntegrity(); + } + + @Test + void clearEmptiesDenseStore() { + TagMap map = map(); + map.set(BASE_SERVICE, "billing"); + map.set(CUSTOM_A, "alpha"); + map.clear(); + assertEquals(0, map.size()); + assertTrue(map.isEmpty()); + assertNull(map.getObject(BASE_SERVICE)); + map.checkIntegrity(); + } + + @Test + void putAllMergesDenseStore() { + TagMap src = map(); + src.set(BASE_SERVICE, "billing"); + src.set(DB_TYPE, "h2"); + src.set(CUSTOM_A, "alpha"); + + TagMap dst = map(); + dst.set(COMPONENT, "web"); // dense, distinct + dst.set(BASE_SERVICE, "old"); // dense, clobbered by src + dst.putAll((TagMap) src); + + assertEquals("billing", dst.getObject(BASE_SERVICE)); // src clobbers + assertEquals("h2", dst.getObject(DB_TYPE)); + assertEquals("web", dst.getObject(COMPONENT)); + assertEquals("alpha", dst.getObject(CUSTOM_A)); + assertEquals(4, dst.size()); + dst.checkIntegrity(); + } + + // ---- read-through union (dense parent + dense child) ---- + + private static TagMap frozenParent() { + TagMap parent = map(); + parent.set(BASE_SERVICE, "billing"); // dense + parent.set(COMPONENT, "web"); // dense + parent.set(CUSTOM_A, "alpha"); // bucket + parent.freeze(); + return parent; + } + + @Test + void childReadsThroughToParentDense() { + TagMap child = TagMap.createFromParent(frozenParent()); + child.set(DB_TYPE, "h2"); // child-only dense + child.set(CUSTOM_B, "beta"); // child-only bucket + + // inherited from parent + assertEquals("billing", child.getObject(BASE_SERVICE)); + assertEquals("web", child.getObject(COMPONENT)); + assertEquals("alpha", child.getObject(CUSTOM_A)); + // own + assertEquals("h2", child.getObject(DB_TYPE)); + assertEquals("beta", child.getObject(CUSTOM_B)); + // union size: 3 parent + 2 child + assertEquals(5, child.size()); + assertFalse(child.isEmpty()); + + Map union = new HashMap<>(); + child.forEach(reader -> union.put(reader.tag(), reader.objectValue())); + assertEquals(5, union.size()); + assertEquals("billing", union.get(BASE_SERVICE)); + assertEquals("h2", union.get(DB_TYPE)); + child.checkIntegrity(); + } + + @Test + void childDenseShadowsParentDense() { + TagMap child = TagMap.createFromParent(frozenParent()); + child.set(BASE_SERVICE, "shipping"); // shadows parent's dense base_service + + assertEquals("shipping", child.getObject(BASE_SERVICE)); // local wins + assertEquals("web", child.getObject(COMPONENT)); // still inherited + assertEquals(3, child.size()); // base_service counted once (shadowed, not doubled) + + Map union = new HashMap<>(); + child.forEach(reader -> union.put(reader.tag(), reader.objectValue())); + assertEquals(3, union.size()); + assertEquals("shipping", union.get(BASE_SERVICE)); // shadow value, parent suppressed + } + + @Test + void removingParentDenseKeyTombstonesIt() { + TagMap child = TagMap.createFromParent(frozenParent()); + + TagMap.Entry removed = child.getAndRemove(BASE_SERVICE); // parent-only dense key + assertEquals("billing", removed.objectValue()); // prior visible value was the parent's + assertNull(child.getObject(BASE_SERVICE)); // tombstoned: no read-through + assertEquals("web", child.getObject(COMPONENT)); // sibling still inherited + assertEquals(2, child.size()); // 3 parent - 1 tombstoned + + Map union = new HashMap<>(); + child.forEach(reader -> union.put(reader.tag(), reader.objectValue())); + assertEquals(2, union.size()); + assertFalse(union.containsKey(BASE_SERVICE)); + child.checkIntegrity(); + } +} diff --git a/internal-api/src/test/java/datadog/trace/api/TagMapDenseFuzzForkedTest.java b/internal-api/src/test/java/datadog/trace/api/TagMapDenseFuzzForkedTest.java new file mode 100644 index 00000000000..a29795c542a --- /dev/null +++ b/internal-api/src/test/java/datadog/trace/api/TagMapDenseFuzzForkedTest.java @@ -0,0 +1,202 @@ +package datadog.trace.api; + +import static org.junit.jupiter.api.Assertions.assertFalse; +import static org.junit.jupiter.api.Assertions.assertTrue; + +import datadog.trace.api.TagMapFuzzTest.MapAction; +import datadog.trace.api.TagMapFuzzTest.TestCase; +import java.util.ArrayList; +import java.util.HashMap; +import java.util.List; +import java.util.concurrent.ThreadLocalRandom; +import java.util.function.Supplier; +import org.junit.jupiter.api.BeforeAll; +import org.junit.jupiter.api.Test; + +/** + * Fuzz test for the dense store under a LIVE resolver, across three key regimes. Reuses {@link + * TagMapFuzzTest}'s oracle machinery ({@code test(TestCase)} replays a random action sequence + * against a {@code HashMap}, verifying each step + {@code checkIntegrity}). + * + *

Uses a synthetic prefix resolver ({@code known-N} -> stored / dense, anything else -> bucket) + * rather than the real {@link KnownTags}: it gives an UNBOUNDED known key space, so the dense array + * actually grows past its initial capacity and the linear scan gets long, and it lets each test pin + * the known/custom ratio. The three regimes exercise paths the mixed run alone would miss: + * + *

+ * + *

Forked (isolated JVM) because resolver registration is a global static with no un-register. + */ +class TagMapDenseFuzzForkedTest { + static final int SINGLE_MAP_CASES = 1500; + static final int MERGE_CASES = 400; + static final int MAX_ACTIONS = 40; + static final int MIN_ACTIONS = 8; + + // unbounded synthetic key spaces — large enough to grow the dense array past cap-8 several times + static final int KNOWN_SPACE = 48; + static final int CUSTOM_SPACE = 48; + + enum Regime { + KNOWN_ONLY, + CUSTOM_ONLY, + MIXED + } + + /** + * Synthetic resolver: {@code known-N} -> stored id (serial = FIRST_STORED_SERIAL + N); else 0. + */ + static final KnownTagCodec.Resolver FUZZ_RESOLVER = + new KnownTagCodec.Resolver() { + @Override + public long keyOf(String name) { + if (name.startsWith("known-")) { + int n = Integer.parseInt(name.substring("known-".length())); + return KnownTagCodec.tagId(KnownTagCodec.FIRST_STORED_SERIAL + n, name); + } + return 0L; + } + + @Override + public String nameOf(long tagId) { + int serial = KnownTagCodec.globalSerial(tagId); + return serial >= KnownTagCodec.FIRST_STORED_SERIAL + ? "known-" + (serial - KnownTagCodec.FIRST_STORED_SERIAL) + : null; + } + + @Override + public int slotCount() { + return 0; // positional unused + } + }; + + @BeforeAll + static void registerResolver() { + KnownTagCodec.register(FUZZ_RESOLVER); + assertTrue(KnownTagCodec.isActive(), "resolver must be live"); + assertTrue(KnownTagCodec.isStored(KnownTagCodec.keyOf("known-0")), "known- routes dense"); + assertFalse( + KnownTagCodec.isStored(KnownTagCodec.keyOf("custom-0")), "custom- stays in buckets"); + // round-trip the synthetic encoding + long id = KnownTagCodec.keyOf("known-7"); + assertTrue("known-7".equals(KnownTagCodec.nameOf(id)), "name<->id round-trips"); + } + + @Test + void knownOnlyFuzz() { + runRegime(Regime.KNOWN_ONLY); + } + + @Test + void customOnlyFuzz() { + runRegime(Regime.CUSTOM_ONLY); + } + + @Test + void mixedFuzz() { + runRegime(Regime.MIXED); + } + + private static void runRegime(Regime regime) { + for (int i = 0; i < SINGLE_MAP_CASES; ++i) { + TagMapFuzzTest.test(generateTest(regime)); + } + for (int i = 0; i < MERGE_CASES; ++i) { + TagMap mapA = TagMapFuzzTest.test(generateTest(regime)); + TagMap mapB = TagMapFuzzTest.test(generateTest(regime)); + + HashMap hashA = new HashMap<>(mapA); + HashMap hashB = new HashMap<>(mapB); + + mapA.putAll(mapB); + hashA.putAll(hashB); + + TagMapFuzzTest.assertMapEquals(hashA, mapA); + } + } + + // --- action generation (mirrors TagMapFuzzTest.randomAction, regime-driven key pool) --- + + private static TestCase generateTest(Regime regime) { + ThreadLocalRandom r = ThreadLocalRandom.current(); + int numActions = r.nextInt(MAX_ACTIONS - MIN_ACTIONS) + MIN_ACTIONS; + List actions = new ArrayList<>(numActions); + for (int i = 0; i < numActions; ++i) { + actions.add(randomAction(regime)); + } + return new TestCase(actions); + } + + private static MapAction randomAction(Regime regime) { + switch (randomChoice(0.02, 0.1, 0.2)) { + case 0: + return TagMapFuzzTest.clear(); + case 1: + return choose( + () -> TagMapFuzzTest.putAll(randomKeysAndValues(regime)), + () -> TagMapFuzzTest.putAllTagMap(randomKeysAndValues(regime)), + () -> TagMapFuzzTest.putAllLedger(randomKeysAndValues(regime))); + case 2: + return choose( + () -> TagMapFuzzTest.remove(randomKey(regime)), + () -> TagMapFuzzTest.removeLight(randomKey(regime)), + () -> TagMapFuzzTest.getAndRemove(randomKey(regime))); + default: + return choose( + () -> TagMapFuzzTest.put(randomKey(regime), randomValue()), + () -> TagMapFuzzTest.set(randomKey(regime), randomValue()), + () -> TagMapFuzzTest.getAndSet(randomKey(regime), randomValue())); + } + } + + private static String randomKey(Regime regime) { + ThreadLocalRandom r = ThreadLocalRandom.current(); + boolean known; + switch (regime) { + case KNOWN_ONLY: + known = true; + break; + case CUSTOM_ONLY: + known = false; + break; + default: + known = r.nextBoolean(); + } + return known ? "known-" + r.nextInt(KNOWN_SPACE) : "custom-" + r.nextInt(CUSTOM_SPACE); + } + + private static String randomValue() { + return "values-" + ThreadLocalRandom.current().nextInt(); + } + + private static String[] randomKeysAndValues(Regime regime) { + int numEntries = ThreadLocalRandom.current().nextInt(KNOWN_SPACE + CUSTOM_SPACE); + String[] keysAndValues = new String[numEntries << 1]; + for (int i = 0; i < keysAndValues.length; i += 2) { + keysAndValues[i] = randomKey(regime); + keysAndValues[i + 1] = randomValue(); + } + return keysAndValues; + } + + private static int randomChoice(double... proportions) { + double selector = ThreadLocalRandom.current().nextDouble(); + for (int i = 0; i < proportions.length; ++i) { + if (selector < proportions[i]) return i; + selector -= proportions[i]; + } + return proportions.length; + } + + @SafeVarargs + private static MapAction choose(Supplier... choices) { + return choices[ThreadLocalRandom.current().nextInt(choices.length)].get(); + } +}