Signed-off-by: Changzhi Xie <s...@qq.com> FUSE Export Coroutine Integration Cover Letter
This patch series refactors QEMU's FUSE export module to leverage coroutines for read/write operations, addressing concurrency limitations and aligning with QEMU's asynchronous I/O model. The changes demonstrate measurable performance improvements while simplifying resource management. 1. Technical Implementation Key modifications address prior review feedback (Stefan Hajnoczi) and optimize execution flow: 1.1 Coroutine Integration Convert fuse_read()/fuse_write() to launch coroutines (fuse_*_coroutine) Utilize non-blocking blk_co_pread()/blk_co_pwrite() for block layer access Eliminate main loop blocking during heavy I/O workloads 1.2 Buffer Management Removed explicit buffer pre-allocation in read_from_fuse_export() Replaced fuse_buf_free() with g_free() due to libfuse3 API constraints 1.3 Resource Lifecycle Moved in_flight decrement and blk_exp_unref() into coroutines Added FUSE opcode checks (FUSE_READ/FUSE_WRITE) to prevent premature cleanup 1.4 Structural Improvements Simplified FuseIORequest structure: Removed redundant fuse_ino_t and fuse_file_info fields Retained minimal parameter passing requirements 2. Performance Validation Tested using fio with 4K random RW pattern, and the result is the average of 5 runs: fio --ioengine=io_uring --numjobs=1 --runtime=30 --ramp_time=5 --rw=randrw --bs=4k --time_based=1 Key Results Metric iodepth=1 iodepth=64 Read Latency ▼ 2.7% (3.8k→3kns) ▼ 1.3% (4.7M→4.6M ns) Write Latency ▼ 3.6% (112k→108kns) ▼ 2.8% (5.2M→5.0M ns) Read IOPS 4740 → 4729 (±0.2%) ▲ 2.1% (6391→6529) Write IOPS 4738 → 4727 (±0.2%) ▲ 2.2% (6390→6529) Throughput ~18.9 GB/s (stable) ▲ 2.1% (25.6→26.1 GB/s) Analysis High Concurrency (iodepth=64): Sustained throughput gains (+2.1-2.2%) demonstrate improved scalability Latency reductions confirm reduced contention in concurrent operations saz97 (1): Integration coroutines into fuse export block/export/fuse.c | 189 +++++++++++++++++++++++++++++++------------- 1 file changed, 132 insertions(+), 57 deletions(-) -- 2.34.1
