On 9/27/19 10:02 AM, Ming Lei wrote:
> Hi Jens,
>
> Looks fio's 'iodepth_batch_submit' is broken.
>
> When running the attached fio script[1], I observed that 'nr' passed to
> io_submit() is 1, except that 64 is only passed to the 1st io_submit().
>
> Then plug merging can't work at all.
>
> [root@ktest-08 tools]# cat bpf
> #include <uapi/linux/aio_abi.h>
> tracepoint:syscalls:sys_enter_io_submit { @nr = hist(args->nr); }
> [root@ktest-08 tools]# bpftrace ./bpf
> Attaching 1 probe...
> ^C
>
> @nr:
> [1] 902349 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@|
> [2, 4) 0 | |
> [4, 8) 0 | |
> [8, 16) 0 | |
> [16, 32) 0 | |
> [32, 64) 0 | |
> [64, 128) 1 | |
>
> [1] fio script:
> fio --readwrite=write --filesize=4g --filename=/dev/sda \
> --runtime=10s --time_based \
> --ioengine=libaio --direct=1 --bs=4k --iodepth=64 \
> --iodepth_batch_submit=64 \
> --numjobs=64 \
> --name=foo
Try adding iodepth_batch_complete as well.
--
Jens Axboe
