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

[Vladimir Homutov]

18.01.2021 11:24, Zhao, Ping пишет:
> Hi Vladimir,
> 
> I tested with response from 4KB to 1MB length which are ok. The procedure is first storing all the cache files on a nvme disk(~20T), then check the iostat & NIC bandwidth since then Nginx will use the cache files on disk with io_uring or libaio. So my patch didn't impact sendfile procedure, it provides another implementation of legacy libaio.
> 
> Regards,
> Ping

yes, I see that your implementation is different.
I wonder, if you can see any difference in performance depending on 
request size? Is it always constant?

> 
> -----Original Message-----
> From: nginx-devel <nginx-devel-bounces at nginx.org> On Behalf Of Vladimir Homutov
> Sent: Monday, January 18, 2021 3:28 PM
> To: nginx-devel at nginx.org
> Subject: Re: [PATCH] Add io_uring support in AIO(async io) module
> 
> 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.
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