From: Jens Axboe <axboe@kernel.dk>
To: Akash Verma <akashv@google.com>, fio <fio@vger.kernel.org>
Cc: Brian Fulton <bfulton@google.com>
Subject: Re: [Bug report] Runtime, IOPS, bandwidth recorded incorrectly if small size with time_based
Date: Mon, 04 May 2015 14:42:06 -0600 [thread overview]
Message-ID: <5547D99E.4080103@kernel.dk> (raw)
In-Reply-To: <CAFFT=UmoooCznxAkUREsC5rGN-hxD++PYbL94s-m11jdycDM0w@mail.gmail.com>
On 04/24/2015 04:50 PM, Akash Verma wrote:
> If there's a load with a very small size, but forced to repeat using
> time_based, the runtime reported at the end, as well as IOPS,
> bandwidth are wrong.
>
> E.g. using this control file:
>
> [short_and_suite]
> rw=randread
> bs=128k
> size=128k
> ioengine=libaio
> time_based=1
> runtime=1
> filename=datafile.tmp
>
> (where datafile.tmp already exists, for a more dramatic demonstration)
> The results I'm seeing on a hard drive are:
> read : io=304128KB, bw=24750MB/s, iops=198000, runt= 12msec
>
> This is a regression from FIO 2.0.5, which gives the following results:
> read : io=242176KB, bw=242418KB/s, iops=1893 , runt= 999msec
>
> which is much more reasonable.
Looks like a shorter run, try runtime=1s. And that makes me wonder if
the default conversion is buggy. What version are you comparing 2.0.5 to?
--
Jens Axboe
next prev parent reply other threads:[~2015-05-04 20:42 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-24 22:50 [Bug report] Runtime, IOPS, bandwidth recorded incorrectly if small size with time_based Akash Verma
2015-05-04 20:42 ` Jens Axboe [this message]
2015-05-04 21:25 ` Brian Fulton
2015-05-04 22:02 ` Jens Axboe
2015-05-04 22:08 ` Jens Axboe
2015-05-04 23:17 ` Brian Fulton
2015-05-05 0:37 ` Jens Axboe
2015-05-05 1:12 ` Brian Fulton
2015-05-15 17:32 ` Brian Fulton
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