From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lb0-f171.google.com ([209.85.217.171]:37174 "EHLO mail-lb0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751801AbaIXJwZ (ORCPT ); Wed, 24 Sep 2014 05:52:25 -0400 Received: by mail-lb0-f171.google.com with SMTP id l4so10349481lbv.16 for ; Wed, 24 Sep 2014 02:52:24 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <54228237.5000805@gmail.com> References: <542179FA.5040106@gmail.com> <54228237.5000805@gmail.com> Date: Wed, 24 Sep 2014 10:52:24 +0100 Message-ID: Subject: Re: [Question] How to perform stride access? From: Sitsofe Wheeler Content-Type: text/plain; charset=UTF-8 Sender: fio-owner@vger.kernel.org List-Id: fio@vger.kernel.org To: Akira Hayakawa Cc: andrey.v.kuzmin@gmail.com, "fio@vger.kernel.org" On 24 September 2014 09:35, Akira Hayakawa wrote: > > However, I [...] think I still have a problem. > > I modified the command > > From: >>> fio --name=test --filename=#{dev.path} --rw=write --ioengine=libaio --direct=1 --io_limit=32M --size=100% --ba=4k --bs=512 > To: > fio --name=test --filename=#{dev.path} --rw=write:4k --ioengine=libaio --direct=1 --io_limit=32M --bs=512 > > The result is the runtime is too short. This looks like a bug. I can reproduce it with 2.1.11-11-gb7f5 too: dd if=/dev/zero of=/dev/shm/1M bs=1M count=1 fio --bs=4k --rw=write:4k --filename=/dev/shm/1M --stonewall --name=1M --io_limit=1M --name=2M --io_limit=2M [...] Run status group 0 (all jobs): WRITE: io=512KB, aggrb=256000KB/s, minb=256000KB/s, maxb=256000KB/s, mint=2msec, maxt=2msec Run status group 1 (all jobs): WRITE: io=512KB, aggrb=256000KB/s, minb=256000KB/s, maxb=256000KB/s, mint=2msec, maxt=2msec Why isn't io 1024KB for group 0? Additionally, shouldn't the total io written each group be different? Jens? > I guess fio stops as soon as it reaches the end of the device. > However, I want it to repeat over and over again until io_limit is fully consumed. > > Note that the device is smaller than 32M (it is only 508B). 508 bytes? But your block size is 512 bytes! Am I misunderstanding what you're doing? > So, it should repeat more than 60 times. > > How can I repeat the workload? number_ios fails too and using zonesize/zoneskip also doesn't help. The only thing left that springs to mind is to use loops or fix this bug :-) > Or, > > Building hand-made random map would suffice, I guess. I'm not sure I follow. The workload you gave above is sequential with holes (--rw=write:4k) - why would we need a random map? -- Sitsofe | http://sucs.org/~sits/