From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from merlin.infradead.org ([205.233.59.134]:51495 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752502Ab3F0JCa (ORCPT ); Thu, 27 Jun 2013 05:02:30 -0400 Date: Thu, 27 Jun 2013 11:02:27 +0200 From: Jens Axboe Subject: Re: Simulating bursts at different rates at irregular intervals? Message-ID: <20130627090227.GL25599@kernel.dk> References: <255129448.30162533.1372322165642.JavaMail.root@framestore.com> <803980722.30163228.1372322272381.JavaMail.root@framestore.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <803980722.30163228.1372322272381.JavaMail.root@framestore.com> Sender: fio-owner@vger.kernel.org List-Id: fio@vger.kernel.org To: James Vanns Cc: fio@vger.kernel.org On Thu, Jun 27 2013, James Vanns wrote: > Hi. I'm new to fio and though I've read the HOWTO from the git repo several times now, I'm unsure if it is possible to achieve what I want; > > I can simulate a mix of sequential and random writes for a duration at > an average rate or throughput of say, 5.4MB/s. I presume that fio > will attempt to sustain that rate? My real question is this - is it > possible in either the same job or a different job in the same file to > simulate bursts of higher rates? I.e. on average attempt to write at > nMB/s but at random or irregular intervals during this period attempt > a 'burst' of 138MB/s for 5 minutes and then return to the 'normal' > rate. Then again at some other point a burst of 57MB/s for 30minutes > etc. > > Is this possible? Presently I've found that I cannot do this. Or > rather, thinking about it, I'd have to specify n jobs for each > different rate and then perhaps use 'ratecycle' and 'thinktime'? I > can't see how to skew 'thinktime' randomly though? That's currently not possible, fio only supports a fixed rate. But if you have a good idea on how to express your criteria as an option (or options), then it can surely be added :-) -- Jens Axboe