block: Batch drain AIO completions in next_completed_request - #7864
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Collect up to 32 completions per io_getevents call instead of one at a time, buffering them in the existing VecDeque. This reduces syscalls from 128 to 4 per drain cycle at the default queue depth. The stack cost is 1 KB per call. Signed-off-by: Anatol Belski <[email protected]>
phip1611
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Mar 19, 2026
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Nice find and thanks for the microbenchmark!
rbradford
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Mar 19, 2026
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Collect up to 32 completions per
io_geteventscall instead of one at a time, buffering them in the existingVecDeque. At the default queue depth of 128, this reduces syscalls from 128 to 4 per drain cycle.The batch size of 32 matches QEMU
DEFAULT_MAX_BATCH. The stack cost is 1 KB per call (32 x 32 byteIoEvent).Micro benchmark results