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https://github.com/cloud-hypervisor/cloud-hypervisor.git
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00957fa9db
Add micro_block_raw_aio_drain_128_us and micro_block_raw_aio_drain_256_us tests that submit N AIO writes to a temporary file, wait for the eventfd signal, then time how long it takes to drain all completions via next_completed_request(). This measures per completion syscall overhead and provides a baseline before any batching optimizations. Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
54 lines
1.7 KiB
Rust
54 lines
1.7 KiB
Rust
// Copyright 2026 The Cloud Hypervisor Authors. All rights reserved.
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//
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// SPDX-License-Identifier: Apache-2.0
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//! In process micro benchmarks for block layer internals.
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//!
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//! These run without booting a VM and measure hot path operations
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//! (e.g. AIO completion draining) at the syscall level.
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use std::os::unix::io::AsRawFd;
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use std::time::Instant;
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use block::async_io::AsyncIo;
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use block::raw_async_aio::RawFileAsyncAio;
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use crate::PerformanceTestControl;
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use crate::util::{self, BLOCK_SIZE};
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/// Submit num_ops AIO writes, wait for them all to land, then time
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/// how long it takes to drain every completion via next_completed_request().
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///
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/// Returns the drain wall clock time in seconds.
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pub fn micro_bench_aio_drain(control: &PerformanceTestControl) -> f64 {
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let num_ops = control.num_ops.expect("num_ops required") as usize;
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let tmp = util::sized_tempfile(num_ops);
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let fd = tmp.as_file().as_raw_fd();
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let mut aio = RawFileAsyncAio::new(fd, num_ops as u32).expect("failed to create AIO context");
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let buf = vec![0xA5u8; BLOCK_SIZE as usize];
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// Submit all writes.
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for i in 0..num_ops {
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let iovec = libc::iovec {
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iov_base: buf.as_ptr() as *mut _,
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iov_len: buf.len(),
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};
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aio.write_vectored((i as u64 * BLOCK_SIZE) as libc::off_t, &[iovec], i as u64)
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.expect("write_vectored failed");
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}
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// Wait until the eventfd signals that completions are available.
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util::wait_for_eventfd(aio.notifier());
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// Drain all completions and measure.
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let start = Instant::now();
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let mut drained = 0usize;
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while drained < num_ops {
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if aio.next_completed_request().is_some() {
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drained += 1;
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}
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}
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start.elapsed().as_secs_f64()
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}
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