From mboxrd@z Thu Jan 1 00:00:00 1970 From: Martin Peschke Subject: Re: [Patch] SCSI statistics Date: Tue, 19 Sep 2006 18:33:14 +0200 Message-ID: <45101BCA.6090608@de.ibm.com> References: <1158578439.3060.50.camel@dyn-9-152-230-71.boeblingen.de.ibm.com> <1158614913.3182.78.camel@laptopd505.fenrus.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mtagate4.uk.ibm.com ([195.212.29.137]:11808 "EHLO mtagate4.uk.ibm.com") by vger.kernel.org with ESMTP id S932314AbWISQd0 (ORCPT ); Tue, 19 Sep 2006 12:33:26 -0400 Received: from d06nrmr1407.portsmouth.uk.ibm.com (d06nrmr1407.portsmouth.uk.ibm.com [9.149.38.185]) by mtagate4.uk.ibm.com (8.13.8/8.13.8) with ESMTP id k8JGXPlg039564 for ; Tue, 19 Sep 2006 16:33:25 GMT Received: from d06av03.portsmouth.uk.ibm.com (d06av03.portsmouth.uk.ibm.com [9.149.37.213]) by d06nrmr1407.portsmouth.uk.ibm.com (8.13.6/8.13.6/NCO v8.1.1) with ESMTP id k8JGZcBv1368112 for ; Tue, 19 Sep 2006 17:35:38 +0100 Received: from d06av03.portsmouth.uk.ibm.com (loopback [127.0.0.1]) by d06av03.portsmouth.uk.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id k8JGXObT013604 for ; Tue, 19 Sep 2006 17:33:24 +0100 In-Reply-To: <1158614913.3182.78.camel@laptopd505.fenrus.org> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Arjan van de Ven Cc: linux-scsi@vger.kernel.org Arjan van de Ven wrote: > On Mon, 2006-09-18 at 13:20 +0200, Martin Peschke wrote: >> This patch makes the SCSI mid layer report statistics data, i.e. request >> sizes, request latencies, request results and queue utilisation. >> For sample output please see below. This data is only gathered if these >> statistics have been enabled by users at run time (default is off). >> >> It is crucial (for us) to be able to look at such kernel level data in >> case of customer situations. It allows us to determine what kind of >> requests might be involved in performance situations. This information >> helps to understand whether one faces a device issue or a Linux issue. >> Not being able to tap into performance data is regarded as a big minus >> by some enterprise customers, who are reluctant to use Linux SCSI >> support or Linux. >> >> Patch is against 2.6.18-rc6-mm2, as it requires the statistics >> infrastructure patches. > > > wouldn't this be nicer as a block level functionality? I won't mind as long as the data closely resembles the actual I/O traffic to and from devices.