From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from merlin.infradead.org ([205.233.59.134]:45460 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753753Ab3GAJ76 (ORCPT ); Mon, 1 Jul 2013 05:59:58 -0400 Date: Mon, 1 Jul 2013 11:59:54 +0200 From: Jens Axboe Subject: Re: Understanding bandwidth results Message-ID: <20130701095954.GK15088@kernel.dk> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: fio-owner@vger.kernel.org List-Id: fio@vger.kernel.org To: Andrew Davidoff Cc: fio@vger.kernel.org On Sun, Jun 30 2013, Andrew Davidoff wrote: > Hi, > > In fio output, I see two values for bandwidth that I'd expect to be > the same, but that are different. For example, in the results from a > sync randread fileio test: > > read : io=182811KB, bw=18279KB/s, iops=18279, runt= 10001msec > ... > bw (KB /s): min= 966, max=21410, per=99.59%, avg=18204.94, stdev=5773.57 > > > I realize they are close, but why are the values for bw= and avg= not > the same? I want to make sure I understand if these are not actually > reporting on the same statistic. > > Also, why is per= not 100%, if this job was run with only a single > thread in a single group? That's just rounding and imprecise math. Should be fixed up though. It's calculated in stat.c:show_ddir_status() and I'll be happy to take patches :-) -- Jens Axboe