[PATCH] Add io_uring support in AIO(async io) module

[Vladimir Homutov]

On Thu, Jan 14, 2021 at 05:53:17AM +0000, Zhao, Ping wrote:
> # HG changeset patch
> # User Ping Zhao <ping.zhao at intel.com>
> # Date 1610554205 18000
> #      Wed Jan 13 11:10:05 2021 -0500
> # Node ID 95886c3353dc80a3da215027c1e0f2141e47e911
> # Parent  b055bb6ef87e49232a7fcb4e5334b8efda3b6499
> Add io_uring support in AIO(async io) module.
>
> Hello, This is a patch to support io_uring in AIO(async io) module.
> Basically you don't need change your configurations. If you're using new kernel(above v5.1) which supports io_uring, and you have   "aio on" in your configuration. Nginx will use io_uring for FILE_AIO access which can achieve performance improvement than legacy   libaio.
>
> Checked with iostat which shows nvme disk io has 30%+ performance improvement with 1 thread.
> Use wrk with 100 threads 200 connections(-t 100 -c 200) with 25000 random requests.
>
>                   iostat(B/s)
> libaio        ~1.0 GB/s
> io_uring   1.3+ GB/s

Hello,

what size of request did you use in your testing?
The previous attempt to use uring
(http://mailman.nginx.org/pipermail/nginx-devel/2020-November/013632.html)
seem to have issues with big requests and fallback to sendfile in such
cases. Note that from the standpoint of HTTP server, most requests are
usually larger than 4Kb.