perf(cli): ship mimalloc in the production feature - #1751
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glibc malloc has no setting that fits a daemon indexing on dozens of worker threads. Measured on beta.41 warming 12 projects: two arenas put 60% of daemon CPU into arena locks; unlimited arenas held 14 GB of freed heap out of 18 GB RSS, and because admission trusts measured RSS the graph never activated again after one peak. Under mimalloc on the same host and corpus the lock share fell to noise and RSS followed live data, 8-13 GB between phases with the same peak, so the resident-memory refusal clears on its own. The production feature now selects alloc-mimalloc, which builds on all four release targets.
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Why an allocator change is the root-cause fix, not a mask
Every previous fix (#1570 token clones,
\bDFA, #1594 arena cap) shared one premise: glibc malloc is the allocator and the code should compensate for it. The census on the live daemon showed glibc has no setting that fits this workload:MALLOC_ARENA_MAX=2(the unit's old cap)__pv_queued_spin_lock_slowpathunder__lll_lock_wait_private;statustook 30.6 s waiting on admissionAdmission trusts measured RSS (
resident_memory.rs), so with glibc the resident-memory policy refused graph activation permanently after one warm peak — the "code graph activation was refused by the resident-memory policy" behind 47 tool refusals in the dogfood run.Measured under mimalloc (same host, same 12 projects, same source)
statustool 30.6 s → 0.14 s.refusedtopending/proceeding.Change
production = ["tracedecay/production", "alloc-mimalloc"]. Release builds use--no-default-features --features production, so this is the shipped allocator on all four targets (verified: the release-profile build linksmi_*). Precedence for overlapping features is unchanged (hotpath-alloc > jemalloc > mimalloc). No code change;malloc_trimreclaimer stays a harmless no-op under mimalloc as its comment already states.Not chosen: jemalloc (tikv-jemallocator has no MSVC support; Windows is a release target).