From: Vincent Fu <vincentfu@gmail.com>
To: Nick Neumann <nick@pcpartpicker.com>, fio@vger.kernel.org
Subject: Re: fio and epoch issues
Date: Fri, 18 Aug 2023 14:58:11 -0400 [thread overview]
Message-ID: <4bd9b597-6221-1f07-991a-d79981d0fc0f@gmail.com> (raw)
In-Reply-To: <CADqNVTqVUra10ET=P+hPA86iimSs3oC7=eWJNdpWjo5e4p+p1g@mail.gmail.com>
On 8/16/23 16:45, Nick Neumann wrote:
> I've tried advocating for this via github issues a couple times
> (https://github.com/axboe/fio/issues/1544,
> https://github.com/axboe/fio/pull/1353/commits) but haven't had much
> luck/interest. I thought I'd try here and see if I could get enough
> interest to get some improvements to fio timekeeping committed. :-)
>
> The main issue is that by default, fio log files use timestamps based
> on an epoch that is the beginning of the job. If you have multiple
> jobs, especially with some jobs waiting on other jobs before starting,
> this means you have different epochs and the times in the logs for
> each job cannot be compared/ordered.
>
> Using log_alternate_epoch solves this problem since with it all logs
> share a common epoch, but introduces a different problem of not
> knowing the start time for each job relative to the common epoch.
>
> Using the default beginning of job epoch for log files, but also
> recording the start time of each job against a common (alternate)
> epoch, would solve both problems and bring other minor benefits too.
>
> Any thoughts? Issue 1544 has a 6-month-old PR that implements this.
> I'm happy to update, make changes, or approach it differently if
> desired.
>
> Thanks,
> Nick
>
I've left feedback at https://github.com/axboe/fio/pull/1353. I think we
should be able to get something done to get this working for you.
Vincent
prev parent reply other threads:[~2023-08-18 18:58 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-16 20:45 fio and epoch issues Nick Neumann
2023-08-18 18:58 ` Vincent Fu [this message]
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