These example targets landed unformatted on main and fail the Rustfmt CI
check (`cargo fmt --all --check`); reformat them so this PR's checks pass.
No logic changes.
Adds Part B (peak RSS for K concurrent decodes) to bench_pool_concurrency and
records the findings in benches/POOL-CONCURRENCY.md.
Honest result: under a 2-core quota the thumbnail decode pool shows flat
throughput, p99, AND peak RSS (137 MiB) from K=1..16 — shrink-on-load already
made each decode RAM-cheap, so over-permitting costs nothing measurable here.
The effective_parallelism() migration is therefore a correctness/consistency
change with no downside, mainly protecting the transcode + ffmpeg pools (and
extreme host-core/quota ratios) this box can't reproduce — not a throughput win.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01JG5yYZ9s868mJwqT2Qz7ez
bench_pool_concurrency drives the real service path (Semaphore(K) gating
spawn_blocking(bench_render_all)) with a gallery of concurrent callers and
sweeps the decode-permit count K, reporting throughput + p50/p99. Run under
taskset to model a CPU quota: it shows the effect of sizing the image pools to
effective_parallelism (K=cores) vs the host count (over-subscribed).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01JG5yYZ9s868mJwqT2Qz7ez
Bradley Nelson