[cknitt]

OCaml 5's allocation report at exit (OCAMLRUNPARAM=v=0x400) only counts the main domain, while the build compiles on worker domains: a clean build of tests/tests reported 3.2M words instead of about 252M.

With REWATCH_REPORT_WORKER_ALLOCATIONS set, the build also prints worker_allocated_words: <n> at exit. Each worker adds its own count (Gc.counters, minor + major − promoted, as the runtime counts) to a shared atomic counter when it stops. Without the variable nothing changes.

This is the base for the build benchmarks in the PR stacked on top, so that their base side reports the workers too. A new check in rewatch-ocaml/tests/run.sh builds a one-module project with the variable set and expects a positive count; the variable is documented in rewatch-ocaml/README.md next to REWATCH_COMPILER_DOMAINS.

🤖 Generated with Claude Code

https://claude.ai/code/session_01Kbf3gGPsF3fHZn9rBxA7Hm

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Semantic Diff

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Report the build's worker allocations when asked

_{a5e4a65 · cknitt + Claude · Nov 09, 2026, 06:45 UTC}

OCaml's allocation report at exit (OCAMLRUNPARAM=v=0x400) counts only the main domain, and the build compiles on worker domains: a clean build of tests/tests reported 3.2M words instead of about 252M. With REWATCH_REPORT_WORKER_ALLOCATIONS set, the build also prints worker_allocated_words: <n>, for the compiler benchmarks.

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✅ Compiler benchmarks

Allocated words

In total: 456,989,425 → 456,989,425 (±0.00%).

None of the 257 benchmarks changed by 0.1% or more.

Instructions

In total: 10,226,961,997 → 10,226,961,997 (±0.00%).

None of the 33 benchmarks changed by 0.1% or more.

Pull request a5e4a65 compared with base d47adb3 in this run.

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