Pulse

Profiling and render instrumentation for Minecraft 1.8.9 (Ornithe / Fabric).

• spark, bundled: /spark on the server and in singleplayer, /sparkc for the client.
• Readable profiles: stack frames are remapped to Feather names before upload, since the spark viewer has no Feather mappings.
• Tracy: run with -Dpulse.tracy=true and connect a Tracy profiler. Every Profiler section in vanilla and in other mods becomes a zone, on both the client and server threads, plus a frame mark per frame. GPU zones are added on Windows and Linux, where the driver provides ARB_timer_query. To capture without the GUI, run tracy-capture -a 127.0.0.1 -o session.tracy. The client library is bundled; it must match your Tracy version (see tracy_version in gradle.properties).
• Startup profiling: run with -Dpulse.profileStartup=true to log how long startup took (loader, game init, first frame) and save a spark profile of it to config/pulse/startup-*.sparkprofile. Sampling starts at mod init, so the loader phase is timed but not profiled.
• Draw calls in F3: per-frame GL draw calls, split into categories (terrain, sky, entities, tiles, particles, text, GUI, other). Counted at the LWJGL level, so draws from mods that bypass vanilla rendering are included.

Requires lenis or legacy-lwjgl3 on the client, and Java 25.