fix: cap BLAS/OpenMP threads to avoid concurrent-proc oversubscription (closes #316)#317
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Sets OMP_NUM_THREADS=1, MKL_NUM_THREADS=1, OPENBLAS_NUM_THREADS=1, NUMEXPR_NUM_THREADS=1 via setdefault in main() before _preload_models(). Why: Claude Code spawns one MCP subprocess per session, and sub-agent fan-out can push this to 10+ concurrent procs on a single host. With default thread counts each proc tries to use every CPU core for PyTorch/sentence-transformers inference. N procs * N cores worth of threads competing for N cores produces a context-switching collapse — empirical symptom is multi-minute m.add() hangs (one confirmed 19-minute hang in ~/.truememory/logs/mcp-debug.log under sub-agent load). setdefault preserves user override: a beefy single-proc workstation can still set OMP_NUM_THREADS=4 etc. explicitly. Co-Authored-By: Claude Opus 4.7 <[email protected]>
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Summary
Caps BLAS/OpenMP threads to 1 per MCP proc via
os.environ.setdefaultinmain()before_preload_models(). Prevents concurrent-proc thread oversubscription that produces multi-minuteengine.add()hangs under Claude Code sub-agent fan-out.Closes #316.
Changes
truememory/mcp_server.pysetdefaultforOMP_NUM_THREADS,MKL_NUM_THREADS,OPENBLAS_NUM_THREADS,NUMEXPR_NUM_THREADSbefore_preload_models()Why
setdefault(not assignment)User override preserved. A beefy single-proc workstation can still set
OMP_NUM_THREADS=4explicitly; the fix only kicks in when the user hasn't expressed an opinion.Test plan
No breaking changes
setdefaultpreserves existing env-var behavior. No public API affected.Co-Authored-By: Claude Opus 4.7 [email protected]