Scan for placeholder markers on the first line#1834
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) (#3499) Add an audit doc designing EMA-driven adaptive sizing for the io_uring registered buffer pool, plus the lightweight telemetry counters that the design depends on. The audit (docs/audits/io-uring-adaptive-buffer-sizing.md) covers: - Where the current sizing constants live (IoUringConfig defaults, for_large_files, for_small_files) and how they reach the pool. - Where to measure miss rate without a syscall on the hot path. - Proposed EMA design: alpha=0.2, WARMUP_SAMPLES=8, geometric grow / linear shrink, hysteresis cooldown, MIN/MAX clamps. - Integration points: Phase 1 (telemetry) lands now; Phase 2 (AdaptiveBufferSizer + resize driver) follows. - Risks: registered-buffer reallocation cost, RLIMIT_MEMLOCK, the 1024-buffer kernel cap, Drop ordering, in-flight SQEs, SQPOLL, per-checkout fetch_add overhead. Telemetry (Phase 1): - RegisteredBufferGroup carries total_acquires / total_misses AtomicU64 counters bumped inside checkout(). Cost is two Relaxed fetch_add per call; sub-percent at line rate. - A new RegisteredBufferStats snapshot type with miss_rate(), modeled on BufferPoolStats in the engine. - RegisteredBufferGroup::stats() accessor. - The stub module mirrors the API so adaptive-sizing logic compiles on non-Linux targets. - Five new unit tests cover the zero state, hit path, miss path, return-does-not-decrement invariant, and the helper math. Phase 2 (the actual AdaptiveBufferSizer + resize cycle) is intentionally not in this PR. The doc is the contract.
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May 5, 2026
) (#3499) Add an audit doc designing EMA-driven adaptive sizing for the io_uring registered buffer pool, plus the lightweight telemetry counters that the design depends on. The audit (docs/audits/io-uring-adaptive-buffer-sizing.md) covers: - Where the current sizing constants live (IoUringConfig defaults, for_large_files, for_small_files) and how they reach the pool. - Where to measure miss rate without a syscall on the hot path. - Proposed EMA design: alpha=0.2, WARMUP_SAMPLES=8, geometric grow / linear shrink, hysteresis cooldown, MIN/MAX clamps. - Integration points: Phase 1 (telemetry) lands now; Phase 2 (AdaptiveBufferSizer + resize driver) follows. - Risks: registered-buffer reallocation cost, RLIMIT_MEMLOCK, the 1024-buffer kernel cap, Drop ordering, in-flight SQEs, SQPOLL, per-checkout fetch_add overhead. Telemetry (Phase 1): - RegisteredBufferGroup carries total_acquires / total_misses AtomicU64 counters bumped inside checkout(). Cost is two Relaxed fetch_add per call; sub-percent at line rate. - A new RegisteredBufferStats snapshot type with miss_rate(), modeled on BufferPoolStats in the engine. - RegisteredBufferGroup::stats() accessor. - The stub module mirrors the API so adaptive-sizing logic compiles on non-Linux targets. - Five new unit tests cover the zero state, hit path, miss path, return-does-not-decrement invariant, and the helper math. Phase 2 (the actual AdaptiveBufferSizer + resize cycle) is intentionally not in this PR. The doc is the contract.
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May 17, 2026
…4204) Add a Criterion benchmark that synthesises 100K, 500K, and 1M out-of-order inserts across drift windows of 32, 256, 2048, and 16K, then reports insert+drain throughput together with the peak occupancy via the `metrics().max_depth` accessor. The benchmark pre-allocates the drifted permutation outside the timed section and prints `max_depth` once per (count, drift) pair so operators can compare against in-flight dispatch capacity and decide whether the spill (#1884) or adaptive-sizing (#1834) paths are warranted. The 1M case is gated behind `BENCH_REORDER_MEMORY_1M=1` to keep default runs fast.
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May 17, 2026
…#1834) (#4216) Records the design and explicit defer recommendation for an EMA-throughput feedback loop over BufferPool soft capacity. Cites current sizing knobs in crates/engine/src/local_copy/buffer_pool/, leverages the existing ThroughputTracker (alpha=0.1) and AdaptiveBufferController instead of introducing parallel state, and lists the bench thresholds prerequisite to shipping the loop.
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May 18, 2026
…4204) Add a Criterion benchmark that synthesises 100K, 500K, and 1M out-of-order inserts across drift windows of 32, 256, 2048, and 16K, then reports insert+drain throughput together with the peak occupancy via the `metrics().max_depth` accessor. The benchmark pre-allocates the drifted permutation outside the timed section and prints `max_depth` once per (count, drift) pair so operators can compare against in-flight dispatch capacity and decide whether the spill (#1884) or adaptive-sizing (#1834) paths are warranted. The 1M case is gated behind `BENCH_REORDER_MEMORY_1M=1` to keep default runs fast.
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May 18, 2026
…#1834) (#4216) Records the design and explicit defer recommendation for an EMA-throughput feedback loop over BufferPool soft capacity. Cites current sizing knobs in crates/engine/src/local_copy/buffer_pool/, leverages the existing ThroughputTracker (alpha=0.1) and AdaptiveBufferController instead of introducing parallel state, and lists the bench thresholds prerequisite to shipping the loop.
oferchen
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May 18, 2026
…4204) Add a Criterion benchmark that synthesises 100K, 500K, and 1M out-of-order inserts across drift windows of 32, 256, 2048, and 16K, then reports insert+drain throughput together with the peak occupancy via the `metrics().max_depth` accessor. The benchmark pre-allocates the drifted permutation outside the timed section and prints `max_depth` once per (count, drift) pair so operators can compare against in-flight dispatch capacity and decide whether the spill (#1884) or adaptive-sizing (#1834) paths are warranted. The 1M case is gated behind `BENCH_REORDER_MEMORY_1M=1` to keep default runs fast.
oferchen
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May 18, 2026
…#1834) (#4216) Records the design and explicit defer recommendation for an EMA-throughput feedback loop over BufferPool soft capacity. Cites current sizing knobs in crates/engine/src/local_copy/buffer_pool/, leverages the existing ThroughputTracker (alpha=0.1) and AdaptiveBufferController instead of introducing parallel state, and lists the bench thresholds prerequisite to shipping the loop.
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Summary
Testing
https://chatgpt.com/codex/tasks/task_e_6905623dcbcc8323ba83d38b782a4ca9