ci: sustained-load GC / allocation profiling (#212) - #314
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Adds a scheduled GC / allocation profile — the sustained-load metrics BDN micro-benchmarks don't capture (gen0/1/2 promotion, LOH pressure, finalizer-queue depth, thread-pool starvation under continuous ETL traffic). - tools/GcProfileWorkload — a workload that runs an in-memory extract -> transform -> load Pipeline (ExtractorBase -> TransformerBase -> LoaderBase, per-stage progress + stage disposal) in a loop for a configurable duration, under ServerGC. - .github/workflows/gc-profile.yaml (weekly Sunday 07:00 UTC + workflow_dispatch) runs the workload for 10 minutes, attaches dotnet-counters by PID to sample the System.Runtime counter set to a CSV, summarises into the step summary, and uploads reports/ as an artifact. - docs/GC-PROFILE.md documents what runs, how to read the report, and the ratchet policy. Gate mode: informational (no regression gate yet — that needs a stable baseline the first several runs establish; same land-informational-harden-later pattern as reproducible-build/semgrep/stryker). Actions SHA-pinned per the repo convention. Validated locally: the workload builds and runs — ~90M records in 8s with only 2 gen0 collections, 0 gen1/gen2, ~6MB allocated (the streaming pipeline is near-zero-alloc per record, consistent with #217). The regression gate is the documented follow-on once baseline runs accumulate. Closes #212 Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
This was referenced Jul 24, 2026
This was referenced Aug 5, 2026
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Summary
Adds a scheduled GC / allocation profile (issue #212) — the sustained-load metrics BDN micro-benchmarks don't capture: gen0/1/2 promotion, LOH pressure, finalizer-queue depth, thread-pool starvation under continuous ETL traffic.
tools/GcProfileWorkload— runs an in-memory extract → transform → loadPipeline(base-classExtractorBase→TransformerBase→LoaderBase, per-stage progress + stage disposal) in a loop for a configurable duration, under ServerGC..github/workflows/gc-profile.yaml(weekly Sun 07:00 UTC +workflow_dispatch,duration_secondsinput) runs the workload 10 min, attachesdotnet-countersby PID →System.Runtimecounters to a CSV, summarises into the step summary, uploadsreports/as an artifact.docs/GC-PROFILE.md— what runs, how to read the report, the ratchet policy.Gate mode: informational — no regression gate yet; that needs a stable baseline the first several runs establish (GC metrics vary more run-to-run than benchmarks). Same land-informational-harden-later pattern as reproducible-build/semgrep/stryker; documented as the follow-on.
Validation
Ran the workload locally — builds clean and produces meaningful telemetry: ~90M records in 8s, 2 gen0 / 0 gen1 / 0 gen2 collections, ~6MB total allocated, ~1MB steady heap. The streaming pipeline is near-zero-alloc per record (consistent with the allocation-free hot-path tests, #217). The workflow's profiling job runs on schedule/dispatch (not this PR).
Acceptance criteria (#212)
GC-PROFILE.md)Closes #212