On Fri, 07 Jul 2023 09:20:07 -0700, Andres Freund wrote:
> I observed poor performance of io_uring compared to synchronous IO. That
> turns out to be caused by deeper CPU idle states entered with io_uring,
> due to io_uring using plain schedule(), whereas synchronous IO uses
> io_schedule().
>
> The losses due to this are substantial. On my cascade lake workstation,
> t/io_uring from the fio repository e.g. yields regressions between 20%
> and 40% with the following command:
> ./t/io_uring -r 5 -X0 -d 1 -s 1 -c 1 -p 0 -S$use_sync -R 0 /mnt/t2/fio/write.0.0
>
> [...]
Applied, thanks!
[1/1] io_uring: Use io_schedule* in cqring wait
(no commit info)
Best regards,
--
Jens Axboe
