From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964892AbWF3BAw (ORCPT ); Thu, 29 Jun 2006 21:00:52 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964895AbWF3BAv (ORCPT ); Thu, 29 Jun 2006 21:00:51 -0400 Received: from mtagate5.uk.ibm.com ([195.212.29.138]:13555 "EHLO mtagate5.uk.ibm.com") by vger.kernel.org with ESMTP id S964892AbWF3BAs (ORCPT ); Thu, 29 Jun 2006 21:00:48 -0400 Message-ID: <44A477BE.6000208@watson.ibm.com> Date: Thu, 29 Jun 2006 21:00:46 -0400 From: Shailabh Nagar User-Agent: Mozilla Thunderbird 1.0.7 (Windows/20050923) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Paul Jackson CC: akpm@osdl.org, Valdis.Kletnieks@vt.edu, jlan@engr.sgi.com, balbir@in.ibm.com, csturtiv@sgi.com, linux-kernel@vger.kernel.org Subject: Re: [Patch][RFC] Disabling per-tgid stats on task exit in taskstats References: <44892610.6040001@watson.ibm.com> <20060623141926.b28a5fc0.akpm@osdl.org> <449C6620.1020203@engr.sgi.com> <20060623164743.c894c314.akpm@osdl.org> <449CAA78.4080902@watson.ibm.com> <20060623213912.96056b02.akpm@osdl.org> <449CD4B3.8020300@watson.ibm.com> <44A01A50.1050403@sgi.com> <20060626105548.edef4c64.akpm@osdl.org> <44A020CD.30903@watson.ibm.com> <20060626111249.7aece36e.akpm@osdl.org> <44A026ED.8080903@sgi.com> <20060626113959.839d72bc.akpm@osdl.org> <44A2F50D.8030306@engr.sgi.com> <20060628145341.529a61ab.akpm@osdl.org> <44A2FC72.9090407@engr.sgi.com> <20060629014050.d3bf0be4.pj@sgi.com> <200606291230.k5TCUg45030710@turing-police.cc.vt.edu> <20060629094408.360ac157.pj@sgi.com> <20060629110107.2e56310b.akpm@osdl.org> <20060629112642.66f35dd5.pj@sgi.com> <44A426DC.9090009@watson.ibm.com> <20060629124148.48d4c9ad.pj@sgi.com> <44A4492E.6090307@watson.ibm.com> <20060629152319.cfffe0d6.pj@sgi.com> <44A46D3B.6060703@watson.ibm.com> <20060629174036.2e592a5b.pj@sgi.! com> In-Reply-To: <20060629174036.2e592a5b.pj@sgi.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Paul Jackson wrote: >Shailabh wrote: > > >>Nope...as long as there are users who are using cpusets ONLY as a means >>of reducing sockets to listen to, timestamps will be needed. >> >> > >Could you take one more stab at explaining this. > >It made no sense to me this time around. Sorry. > > > In the current taskstats interface, there is only a single stream of taskstats structures coming out from the kernel. There is some ordering there. Lets say this ordering info is of some relevance to a consumer of taskstats (very big and possibly faulty assumption there !) Now we move to a design where the kernel is sending the same data out in multiple streams. If the consumer wants to reconstruct the ordering she would have got under the current scheme (even approximately), she would need to know how to merge sort these streams and for that she would need timestamp data on each of the taskstats structs. Assumption is a bit of a stretch admittedly. But since timestamping costs so little, might as well put one in (will also help CSA do one less thing) --Shailabh