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Message-ID: <6a5feb66-632f-b843-c04d-e0aaa2d51415@grimberg.me>
Date: Wed, 19 Apr 2023 16:15:47 +0300
From: Sagi Grimberg <sagi@...mberg.me>
To: Daniel Wagner <dwagner@...e.de>
Cc: Chaitanya Kulkarni <chaitanyak@...dia.com>,
"linux-nvme@...ts.infradead.org" <linux-nvme@...ts.infradead.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"linux-block@...r.kernel.org" <linux-block@...r.kernel.org>,
Shin'ichiro Kawasaki <shinichiro@...tmail.com>
Subject: Re: [RFC v1 0/1] nvme testsuite runtime optimization
>>>> While testing the fc transport I got a bit tired of wait for the I/O jobs to
>>>> finish. Thus here some runtime optimization.
>>>>
>>>> With a small/slow VM I got following values:
>>>>
>>>> with 'optimizations'
>>>> loop:
>>>> real 4m43.981s
>>>> user 0m17.754s
>>>> sys 2m6.249s
>>
>> How come loop is doubling the time with this patch?
>> ratio is not the same before and after.
>
> first run was with loop, second one with rdma:
>
> nvme/002 (create many subsystems and test discovery) [not run]
> runtime 82.089s ...
> nvme_trtype=rdma is not supported in this test
>
> nvme/016 (create/delete many NVMeOF block device-backed ns and test discovery) [not run]
> runtime 39.948s ...
> nvme_trtype=rdma is not supported in this test
> nvme/017 (create/delete many file-ns and test discovery) [not run]
> runtime 40.237s ...
>
> nvme/047 (test different queue types for fabric transports) [passed]
> runtime ... 13.580s
> nvme/048 (Test queue count changes on reconnect) [passed]
> runtime ... 6.287s
>
> 82 + 40 + 40 - 14 - 6 = 142. So loop runs additional tests. Hmm, though my
> optimization didn't work there...
How come loop is 4m+ while the others are 2m+ when before all
were the same timeframe more or less?
>
>>> Those jobs are meant to be run for at least 1G to establish
>>> confidence on the data set and the system under test since SSDs
>>> are in TBs nowadays and we don't even get anywhere close to that,
>>> with your suggestion we are going even lower ...
>>
>> Where does the 1G boundary coming from?
>
> No idea, it just the existing hard coded values. I guess it might be from
> efa06fcf3c83 ("loop: test partition scanning") which was the first real test
> case (according the logs).
Was asking Chaitanya why is 1G considered sufficient vs. other sizes?
Why not 10G? Why not 100M?
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