On Mon, Aug 02, 2021 at 11:51:56AM +0800, brookxu wrote: > From: Chunguang Xu <brookxu@xxxxxxxxxxx> > > After patch 54efd50 (block: make generic_make_request handle > arbitrarily sized bios), the IO through io-throttle may be larger, > and these IOs may be further split into more small IOs. However, > IOPS throttle does not seem to be aware of this change, which > makes the calculation of IOPS of large IOs incomplete, resulting > in disk-side IOPS that does not meet expectations. Maybe we should > fix this problem. > > We can reproduce it by set max_sectors_kb of disk to 128, set > blkio.write_iops_throttle to 100, run a dd instance inside blkio > and use iostat to watch IOPS: > > dd if=/dev/zero of=/dev/sdb bs=1M count=1000 oflag=direct > > As a result, without this change the average IOPS is 1995, with > this change the IOPS is 98. > > v3: Optimize the use of atomic variables. > v2: Use atomic variables to solve synchronization problems. > > Signed-off-by: Chunguang Xu <brookxu@xxxxxxxxxxx> Acked-by: Tejun Heo <tj@xxxxxxxxxx> Thanks. -- tejun
