perf(diskann): async I/O overlap and dynamic beam - #617
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richyreachy wants to merge 12 commits into
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Jul 27, 2026
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| uint32_t num_ios = 0; | ||
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| uint32_t effective_beam_width = |
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sector_buffer_ 可能会因为这个改动越界。比如这个值是32，要写入4096维的FP32，sector = ceil(16788 / 4096) = 5，32 * 5就会超过kMaxSectorReadNum = 128
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| int ret = LibAioLoader::Instance().io_submit(ctx, (int64_t)n_ops, | ||
| batch.cb_ptrs.data()); | ||
| if (ret == (int)n_ops) { |
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如果还有正在异步处理的请求，这个条件不满足，不应该被视为失败降级pread
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| for (int i = 0; i < ret; i++) { | ||
| uint32_t idx = (uint32_t)(uintptr_t)evts[i].data; | ||
| if ((int64_t)evts[i].res != (int64_t)batch.cbs[idx].u.c.nbytes) { |
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这里应该是要异常处理的，不能直接往completed_indices里丢。必要时可能要考虑降级。
| if (min_req < 1) min_req = 1; | ||
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| std::vector<io_event_t> evts(n_remaining); | ||
| int ret = LibAioLoader::Instance().io_getevents( |
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Returning here leaves submitted AIO requests unquiesced. For example, -EINTR may occur while requests are still in flight; they can later overwrite the shared sector buffer or leave completion events that the next PendingBatch misattributes to its own requests. Retry EINTR; for permanent failures, drain or destroy/recreate the AIO context before returning.
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Optimizes DiskANN beam search to overlap CPU computation with disk I/O, reducing query latency on disk-bound workloads. By introducing the following improvement:
Add async I/O submit/get_completed pattern to allow CPU work to proceed while disk reads still in progress.
Add dynamic beam width to ensure sufficient I/O parallelism while preventing excessive concurrent I/Os.
Fix Visit-filter deduplication to avoid redundant candidate insertions for already-visited nodes.