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Merged
dirkjink merged 1 commit into from
Sep 7, 2026
Merged

Keep the send callback scalar-replaceable: drop the volatile flag #21

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8 changes: 8 additions & 0 deletions CHANGELOG.md
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Original file line number Diff line number Diff line change
Expand Up @@ -89,6 +89,14 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
- Shared test support (`RecordingAppender`, `RecordingProducerFactory`,
three encoders) replaces the per-class private fixtures; every test
fixture closes what it starts.
- The per-send callback's synchronous-failure flag is a plain field (the
race with an asynchronous error callback is benign in both outcomes),
so the JIT can scalar-replace the callback wherever it does not
escape; `SenderPathBenchmark` unbound is back at its 2026-08-30
allocation baseline (112 B/op). The metrics-bound variant reads
224 B/op in this session for the pre-change code as well (same JVM;
JIT-profile variance the benchmark report already documents), so it
carries no regression either.

### Fixed

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361 changes: 361 additions & 0 deletions benchmarks/results/2026-09-07/r2-senderpath-after-volatile-removal.txt
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@@ -0,0 +1,361 @@
WARNING: A terminally deprecated method in sun.misc.Unsafe has been called
WARNING: sun.misc.Unsafe::objectFieldOffset has been called by org.openjdk.jmh.util.Utils (file:/home/dirk/IdeaProjects/tabellarium/benchmarks/target/benchmarks.jar)
WARNING: Please consider reporting this to the maintainers of class org.openjdk.jmh.util.Utils
WARNING: sun.misc.Unsafe::objectFieldOffset will be removed in a future release
# JMH version: 1.37
# VM version: JDK 26.0.1, Java HotSpot(TM) 64-Bit Server VM, 26.0.1+8-34
# VM invoker: /usr/lib/jvm/jdk-26.0.1-oracle-x64/bin/java
# VM options: <none>
# Blackhole mode: compiler (auto-detected, use -Djmh.blackhole.autoDetect=false to disable)
# Warmup: 5 iterations, 1 s each
# Measurement: 5 iterations, 1 s each
# Timeout: 10 min per iteration
# Threads: 1 thread, will synchronize iterations
# Benchmark mode: Average time, time/op
# Benchmark: eu.inqudium.tabellarium.bench.SenderPathBenchmark.sendOneEvent
# Parameters: (metricsBound = false)

# Run progress: 0,00% complete, ETA 00:01:00
# Fork: 1 of 3
WARNING: A terminally deprecated method in sun.misc.Unsafe has been called
WARNING: sun.misc.Unsafe::objectFieldOffset has been called by org.openjdk.jmh.util.Utils (file:/home/dirk/IdeaProjects/tabellarium/benchmarks/target/benchmarks.jar)
WARNING: Please consider reporting this to the maintainers of class org.openjdk.jmh.util.Utils
WARNING: sun.misc.Unsafe::objectFieldOffset will be removed in a future release
# Warmup Iteration 1: 76,670 ns/op
# Warmup Iteration 2: 66,626 ns/op
# Warmup Iteration 3: 67,638 ns/op
# Warmup Iteration 4: 66,891 ns/op
# Warmup Iteration 5: 71,250 ns/op
Iteration 1: 67,133 ns/op
gc.alloc.rate: 1590,741 MB/sec
gc.alloc.rate.norm: 112,000 B/op
gc.count: 5,000 counts
gc.time: 2,000 ms

Iteration 2: 68,685 ns/op
gc.alloc.rate: 1554,752 MB/sec
gc.alloc.rate.norm: 112,000 B/op
gc.count: 5,000 counts
gc.time: 2,000 ms

Iteration 3: 67,269 ns/op
gc.alloc.rate: 1587,533 MB/sec
gc.alloc.rate.norm: 112,000 B/op
gc.count: 6,000 counts
gc.time: 3,000 ms

Iteration 4: 67,968 ns/op
gc.alloc.rate: 1571,132 MB/sec
gc.alloc.rate.norm: 112,000 B/op
gc.count: 5,000 counts
gc.time: 3,000 ms

Iteration 5: 66,754 ns/op
gc.alloc.rate: 1599,666 MB/sec
gc.alloc.rate.norm: 112,000 B/op
gc.count: 6,000 counts
gc.time: 3,000 ms


# Run progress: 16,67% complete, ETA 00:00:52
# Fork: 2 of 3
WARNING: A terminally deprecated method in sun.misc.Unsafe has been called
WARNING: sun.misc.Unsafe::objectFieldOffset has been called by org.openjdk.jmh.util.Utils (file:/home/dirk/IdeaProjects/tabellarium/benchmarks/target/benchmarks.jar)
WARNING: Please consider reporting this to the maintainers of class org.openjdk.jmh.util.Utils
WARNING: sun.misc.Unsafe::objectFieldOffset will be removed in a future release
# Warmup Iteration 1: 100,839 ns/op
# Warmup Iteration 2: 68,263 ns/op
# Warmup Iteration 3: 67,826 ns/op
# Warmup Iteration 4: 67,242 ns/op
# Warmup Iteration 5: 67,162 ns/op
Iteration 1: 67,012 ns/op
gc.alloc.rate: 1593,538 MB/sec
gc.alloc.rate.norm: 112,000 B/op
gc.count: 5,000 counts
gc.time: 4,000 ms

Iteration 2: 67,350 ns/op
gc.alloc.rate: 1585,500 MB/sec
gc.alloc.rate.norm: 112,000 B/op
gc.count: 5,000 counts
gc.time: 4,000 ms

Iteration 3: 66,964 ns/op
gc.alloc.rate: 1594,790 MB/sec
gc.alloc.rate.norm: 112,000 B/op
gc.count: 6,000 counts
gc.time: 5,000 ms

Iteration 4: 66,960 ns/op
gc.alloc.rate: 1594,626 MB/sec
gc.alloc.rate.norm: 112,000 B/op
gc.count: 5,000 counts
gc.time: 3,000 ms

Iteration 5: 67,079 ns/op
gc.alloc.rate: 1590,401 MB/sec
gc.alloc.rate.norm: 112,000 B/op
gc.count: 5,000 counts
gc.time: 5,000 ms


# Run progress: 33,33% complete, ETA 00:00:41
# Fork: 3 of 3
WARNING: A terminally deprecated method in sun.misc.Unsafe has been called
WARNING: sun.misc.Unsafe::objectFieldOffset has been called by org.openjdk.jmh.util.Utils (file:/home/dirk/IdeaProjects/tabellarium/benchmarks/target/benchmarks.jar)
WARNING: Please consider reporting this to the maintainers of class org.openjdk.jmh.util.Utils
WARNING: sun.misc.Unsafe::objectFieldOffset will be removed in a future release
# Warmup Iteration 1: 77,078 ns/op
# Warmup Iteration 2: 77,730 ns/op
# Warmup Iteration 3: 68,566 ns/op
# Warmup Iteration 4: 69,929 ns/op
# Warmup Iteration 5: 66,102 ns/op
Iteration 1: 73,035 ns/op
gc.alloc.rate: 1461,983 MB/sec
gc.alloc.rate.norm: 112,001 B/op
gc.count: 1,000 counts
gc.time: 1,000 ms

Iteration 2: 65,523 ns/op
gc.alloc.rate: 1629,680 MB/sec
gc.alloc.rate.norm: 112,000 B/op
gc.count: 2,000 counts
gc.time: 3,000 ms

Iteration 3: 65,270 ns/op
gc.alloc.rate: 1635,738 MB/sec
gc.alloc.rate.norm: 112,000 B/op
gc.count: 2,000 counts
gc.time: 2,000 ms

Iteration 4: 66,441 ns/op
gc.alloc.rate: 1607,144 MB/sec
gc.alloc.rate.norm: 112,000 B/op
gc.count: 1,000 counts
gc.time: 1,000 ms

Iteration 5: 65,188 ns/op
gc.alloc.rate: 1638,018 MB/sec
gc.alloc.rate.norm: 112,000 B/op
gc.count: 2,000 counts
gc.time: 2,000 ms



Result "eu.inqudium.tabellarium.bench.SenderPathBenchmark.sendOneEvent":
67,242 ±(99.9%) 1,987 ns/op [Average]
(min, avg, max) = (65,188, 67,242, 73,035), stdev = 1,859
CI (99.9%): [65,255, 69,229] (assumes normal distribution)

Secondary result "eu.inqudium.tabellarium.bench.SenderPathBenchmark.sendOneEvent:gc.alloc.rate":
1589,016 ±(99.9%) 44,645 MB/sec [Average]
(min, avg, max) = (1461,983, 1589,016, 1638,018), stdev = 41,761
CI (99.9%): [1544,371, 1633,661] (assumes normal distribution)

Secondary result "eu.inqudium.tabellarium.bench.SenderPathBenchmark.sendOneEvent:gc.alloc.rate.norm":
112,000 ±(99.9%) 0,001 B/op [Average]
(min, avg, max) = (112,000, 112,000, 112,001), stdev = 0,001
CI (99.9%): [112,000, 112,000] (assumes normal distribution)

Secondary result "eu.inqudium.tabellarium.bench.SenderPathBenchmark.sendOneEvent:gc.count":
61,000 ±(99.9%) 0,001 counts [Sum]
(min, avg, max) = (1,000, 4,067, 6,000), stdev = 1,870
CI (99.9%): [61,000, 61,000] (assumes normal distribution)

Secondary result "eu.inqudium.tabellarium.bench.SenderPathBenchmark.sendOneEvent:gc.time":
43,000 ±(99.9%) 0,001 ms [Sum]
(min, avg, max) = (1,000, 2,867, 5,000), stdev = 1,246
CI (99.9%): [43,000, 43,000] (assumes normal distribution)


# JMH version: 1.37
# VM version: JDK 26.0.1, Java HotSpot(TM) 64-Bit Server VM, 26.0.1+8-34
# VM invoker: /usr/lib/jvm/jdk-26.0.1-oracle-x64/bin/java
# VM options: <none>
# Blackhole mode: compiler (auto-detected, use -Djmh.blackhole.autoDetect=false to disable)
# Warmup: 5 iterations, 1 s each
# Measurement: 5 iterations, 1 s each
# Timeout: 10 min per iteration
# Threads: 1 thread, will synchronize iterations
# Benchmark mode: Average time, time/op
# Benchmark: eu.inqudium.tabellarium.bench.SenderPathBenchmark.sendOneEvent
# Parameters: (metricsBound = true)

# Run progress: 50,00% complete, ETA 00:00:31
# Fork: 1 of 3
WARNING: A terminally deprecated method in sun.misc.Unsafe has been called
WARNING: sun.misc.Unsafe::objectFieldOffset has been called by org.openjdk.jmh.util.Utils (file:/home/dirk/IdeaProjects/tabellarium/benchmarks/target/benchmarks.jar)
WARNING: Please consider reporting this to the maintainers of class org.openjdk.jmh.util.Utils
WARNING: sun.misc.Unsafe::objectFieldOffset will be removed in a future release
# Warmup Iteration 1: 222,503 ns/op
# Warmup Iteration 2: 189,291 ns/op
# Warmup Iteration 3: 188,565 ns/op
# Warmup Iteration 4: 187,677 ns/op
# Warmup Iteration 5: 186,633 ns/op
Iteration 1: 187,271 ns/op
gc.alloc.rate: 1140,299 MB/sec
gc.alloc.rate.norm: 224,001 B/op
gc.count: 3,000 counts
gc.time: 3,000 ms

Iteration 2: 186,802 ns/op
gc.alloc.rate: 1143,158 MB/sec
gc.alloc.rate.norm: 224,001 B/op
gc.count: 4,000 counts
gc.time: 4,000 ms

Iteration 3: 188,827 ns/op
gc.alloc.rate: 1130,926 MB/sec
gc.alloc.rate.norm: 224,001 B/op
gc.count: 3,000 counts
gc.time: 3,000 ms

Iteration 4: 188,111 ns/op
gc.alloc.rate: 1135,190 MB/sec
gc.alloc.rate.norm: 224,001 B/op
gc.count: 4,000 counts
gc.time: 4,000 ms

Iteration 5: 186,493 ns/op
gc.alloc.rate: 1145,154 MB/sec
gc.alloc.rate.norm: 224,001 B/op
gc.count: 4,000 counts
gc.time: 3,000 ms


# Run progress: 66,67% complete, ETA 00:00:20
# Fork: 2 of 3
WARNING: A terminally deprecated method in sun.misc.Unsafe has been called
WARNING: sun.misc.Unsafe::objectFieldOffset has been called by org.openjdk.jmh.util.Utils (file:/home/dirk/IdeaProjects/tabellarium/benchmarks/target/benchmarks.jar)
WARNING: Please consider reporting this to the maintainers of class org.openjdk.jmh.util.Utils
WARNING: sun.misc.Unsafe::objectFieldOffset will be removed in a future release
# Warmup Iteration 1: 222,096 ns/op
# Warmup Iteration 2: 189,077 ns/op
# Warmup Iteration 3: 187,612 ns/op
# Warmup Iteration 4: 191,975 ns/op
# Warmup Iteration 5: 196,034 ns/op
Iteration 1: 215,751 ns/op
gc.alloc.rate: 988,811 MB/sec
gc.alloc.rate.norm: 224,002 B/op
gc.count: 4,000 counts
gc.time: 8,000 ms

Iteration 2: 189,917 ns/op
gc.alloc.rate: 1124,616 MB/sec
gc.alloc.rate.norm: 224,001 B/op
gc.count: 3,000 counts
gc.time: 2,000 ms

Iteration 3: 189,328 ns/op
gc.alloc.rate: 1128,089 MB/sec
gc.alloc.rate.norm: 224,001 B/op
gc.count: 4,000 counts
gc.time: 3,000 ms

Iteration 4: 191,203 ns/op
gc.alloc.rate: 1116,945 MB/sec
gc.alloc.rate.norm: 224,001 B/op
gc.count: 3,000 counts
gc.time: 3,000 ms

Iteration 5: 188,867 ns/op
gc.alloc.rate: 1130,621 MB/sec
gc.alloc.rate.norm: 224,001 B/op
gc.count: 4,000 counts
gc.time: 2,000 ms


# Run progress: 83,33% complete, ETA 00:00:10
# Fork: 3 of 3
WARNING: A terminally deprecated method in sun.misc.Unsafe has been called
WARNING: sun.misc.Unsafe::objectFieldOffset has been called by org.openjdk.jmh.util.Utils (file:/home/dirk/IdeaProjects/tabellarium/benchmarks/target/benchmarks.jar)
WARNING: Please consider reporting this to the maintainers of class org.openjdk.jmh.util.Utils
WARNING: sun.misc.Unsafe::objectFieldOffset will be removed in a future release
# Warmup Iteration 1: 220,256 ns/op
# Warmup Iteration 2: 188,279 ns/op
# Warmup Iteration 3: 201,731 ns/op
# Warmup Iteration 4: 189,906 ns/op
# Warmup Iteration 5: 191,333 ns/op
Iteration 1: 192,125 ns/op
gc.alloc.rate: 1588,067 MB/sec
gc.alloc.rate.norm: 320,001 B/op
gc.count: 3,000 counts
gc.time: 3,000 ms

Iteration 2: 193,856 ns/op
gc.alloc.rate: 1573,864 MB/sec
gc.alloc.rate.norm: 320,001 B/op
gc.count: 4,000 counts
gc.time: 3,000 ms

Iteration 3: 198,412 ns/op
gc.alloc.rate: 1537,710 MB/sec
gc.alloc.rate.norm: 320,001 B/op
gc.count: 4,000 counts
gc.time: 4,000 ms

Iteration 4: 206,110 ns/op
gc.alloc.rate: 1479,724 MB/sec
gc.alloc.rate.norm: 320,001 B/op
gc.count: 4,000 counts
gc.time: 3,000 ms

Iteration 5: 209,551 ns/op
gc.alloc.rate: 1455,588 MB/sec
gc.alloc.rate.norm: 320,001 B/op
gc.count: 4,000 counts
gc.time: 3,000 ms



Result "eu.inqudium.tabellarium.bench.SenderPathBenchmark.sendOneEvent":
194,175 ±(99.9%) 9,780 ns/op [Average]
(min, avg, max) = (186,493, 194,175, 215,751), stdev = 9,148
CI (99.9%): [184,395, 203,955] (assumes normal distribution)

Secondary result "eu.inqudium.tabellarium.bench.SenderPathBenchmark.sendOneEvent:gc.alloc.rate":
1254,584 ±(99.9%) 219,323 MB/sec [Average]
(min, avg, max) = (988,811, 1254,584, 1588,067), stdev = 205,155
CI (99.9%): [1035,261, 1473,907] (assumes normal distribution)

Secondary result "eu.inqudium.tabellarium.bench.SenderPathBenchmark.sendOneEvent:gc.alloc.rate.norm":
256,001 ±(99.9%) 50,078 B/op [Average]
(min, avg, max) = (224,001, 256,001, 320,001), stdev = 46,843
CI (99.9%): [205,923, 306,080] (assumes normal distribution)

Secondary result "eu.inqudium.tabellarium.bench.SenderPathBenchmark.sendOneEvent:gc.count":
55,000 ±(99.9%) 0,001 counts [Sum]
(min, avg, max) = (3,000, 3,667, 4,000), stdev = 0,488
CI (99.9%): [55,000, 55,000] (assumes normal distribution)

Secondary result "eu.inqudium.tabellarium.bench.SenderPathBenchmark.sendOneEvent:gc.time":
51,000 ±(99.9%) 0,001 ms [Sum]
(min, avg, max) = (2,000, 3,400, 8,000), stdev = 1,404
CI (99.9%): [51,000, 51,000] (assumes normal distribution)


# Run complete. Total time: 00:01:02

REMEMBER: The numbers below are just data. To gain reusable insights, you need to follow up on
why the numbers are the way they are. Use profilers (see -prof, -lprof), design factorial
experiments, perform baseline and negative tests that provide experimental control, make sure
the benchmarking environment is safe on JVM/OS/HW level, ask for reviews from the domain experts.
Do not assume the numbers tell you what you want them to tell.

NOTE: Current JVM experimentally supports Compiler Blackholes, and they are in use. Please exercise
extra caution when trusting the results, look into the generated code to check the benchmark still
works, and factor in a small probability of new VM bugs. Additionally, while comparisons between
different JVMs are already problematic, the performance difference caused by different Blackhole
modes can be very significant. Please make sure you use the consistent Blackhole mode for comparisons.

Benchmark (metricsBound) Mode Cnt Score Error Units
SenderPathBenchmark.sendOneEvent false avgt 15 67,242 ± 1,987 ns/op
SenderPathBenchmark.sendOneEvent:gc.alloc.rate false avgt 15 1589,016 ± 44,645 MB/sec
SenderPathBenchmark.sendOneEvent:gc.alloc.rate.norm false avgt 15 112,000 ± 0,001 B/op
SenderPathBenchmark.sendOneEvent:gc.count false avgt 15 61,000 counts
SenderPathBenchmark.sendOneEvent:gc.time false avgt 15 43,000 ms
SenderPathBenchmark.sendOneEvent true avgt 15 194,175 ± 9,780 ns/op
SenderPathBenchmark.sendOneEvent:gc.alloc.rate true avgt 15 1254,584 ± 219,323 MB/sec
SenderPathBenchmark.sendOneEvent:gc.alloc.rate.norm true avgt 15 256,001 ± 50,078 B/op
SenderPathBenchmark.sendOneEvent:gc.count true avgt 15 55,000 counts
SenderPathBenchmark.sendOneEvent:gc.time true avgt 15 51,000 ms
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