From: Jens Axboe <axboe@kernel.dk>
To: Dennis Jacobfeuerborn <dennisml@conversis.de>
Cc: Erwan Velu <erwan@enovance.com>,
"fio@vger.kernel.org" <fio@vger.kernel.org>
Subject: Re: no slat log
Date: Thu, 08 Aug 2013 14:55:48 -0600 [thread overview]
Message-ID: <520405D4.2060309@kernel.dk> (raw)
In-Reply-To: <52022323.2030208@conversis.de>
On 08/07/2013 04:36 AM, Dennis Jacobfeuerborn wrote:
> On 07.08.2013 11:10, Erwan Velu wrote:
>> On 07/08/2013 00:08, Dennis Jacobfeuerborn wrote:
>>> Hi,
>>> when I try to create logs with fio I get bw, iops, lat, clat and slat
>>> logs but the slat log always has a size of 0 bytes. Is this a bug or
>>> is data for this log only generated with specific options for fio?
>>>
>> Dennis,
>>
>> I've been trying this on my 2.1.2 with the following job :
>>
>> [read-sda-4k-para]
>> bs=4k
>> filename=/dev/sda
>> rw=read
>> write_lat_log=lat.log
>>
>> On my side, the slat file is perfectly filled.
>>
>> Can you provide a testing procedure & the version you use ?
>
> I just tested the job above and these are the files produced:
>
> [dennis@nexus fio]$ ls -l
> total 11272
> -rw-r--r--. 1 root root 5767080 7. Aug 12:31 lat.log_clat.log
> -rw-r--r--. 1 root root 5767087 7. Aug 12:31 lat.log_lat.log
> -rw-r--r--. 1 root root 0 7. Aug 12:31 lat.log_slat.log
> -rw-rw-r--. 1 dennis dennis 84 7. Aug 12:31 logtest.fio
>
> There are not errors or warnings during the fio run so it's not clear
> why the file ends up being empty.
slat only exists for async IO engines. For a sync workload, submission
and completion retrieval are not separate events, so you cannot do split
submission + completion stats.
--
Jens Axboe
prev parent reply other threads:[~2013-08-08 20:56 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-06 22:08 no slat log Dennis Jacobfeuerborn
2013-08-07 9:10 ` Erwan Velu
2013-08-07 10:36 ` Dennis Jacobfeuerborn
2013-08-07 12:30 ` Erwan Velu
2013-08-08 20:55 ` Jens Axboe [this message]
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