From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:50905 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755916Ab2DEUXr convert rfc822-to-8bit (ORCPT ); Thu, 5 Apr 2012 16:23:47 -0400 Received: from pps.filterd (m0004060 [127.0.0.1]) by mx0b-00082601.pphosted.com (8.14.4/8.14.4) with SMTP id q35KIPtv002803 for ; Thu, 5 Apr 2012 13:23:46 -0700 Received: from mail.thefacebook.com (corpout1.snc1.tfbnw.net [66.220.144.38]) by mx0b-00082601.pphosted.com with ESMTP id 141hmkr2kd-1 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=NOT) for ; Thu, 05 Apr 2012 13:23:46 -0700 From: Lucian Grijincu Subject: difference between "bandwidth (KB/s)" and "Bw (KB/s) mean" Date: Thu, 5 Apr 2012 20:23:44 +0000 Message-ID: In-Reply-To: Content-Language: en-US Content-Type: text/plain; charset="us-ascii" Content-ID: <210CD586C6A35C459F4CAB4F99A30BE8@fb.com> Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: fio-owner@vger.kernel.org List-Id: fio@vger.kernel.org To: "fio@vger.kernel.org" I was expecting these two to be the same value. You give this example in the HOWTO: write: io= 32MB, bw= 666KB/s, iops=89 , runt= 50320msec slat (msec): min= 0, max= 136, avg= 0.03, stdev= 1.92 clat (msec): min= 0, max= 631, avg=48.50, stdev=86.82 bw (KB/s) : min= 0, max= 1196, per=51.00%, avg=664.02, stdev=681.68 There's a small difference between them: 666KB/s vs 664.02KB/s bw= Average bandwidth rate bw=Bandwidth. Same names as the xlat stats, but also includes an approximate percentage of total aggregate bandwidth this thread received in this group. This last value is slat=Submission latency (avg being the average, stdev being the standard deviation). >From these descriptions I'd guess they are supposed to be the same value. >From tests I can see big differences between them (at least with group_reporting): - bandwidth (KB/s) - increases with number of threads and plateaus - Bw (KB/s) mean - decreases with number of threads and plateaus -- Lucian