Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965153AbVKPBod (ORCPT ); Tue, 15 Nov 2005 20:44:33 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965154AbVKPBod (ORCPT ); Tue, 15 Nov 2005 20:44:33 -0500 Received: from e4.ny.us.ibm.com ([32.97.182.144]:10706 "EHLO e4.ny.us.ibm.com") by vger.kernel.org with ESMTP id S965153AbVKPBoc (ORCPT ); Tue, 15 Nov 2005 20:44:32 -0500 Message-ID: <437A8FED.3080508@watson.ibm.com> Date: Tue, 15 Nov 2005 20:48:29 -0500 From: Shailabh Nagar Reply-To: nagar@watson.ibm.com User-Agent: Mozilla Thunderbird 1.0.2 (Windows/20050317) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Peter Chubb CC: Andrew Morton , linux-kernel@vger.kernel.org, Ingo Molnar , Andi Kleen Subject: Re: [Patch 1/4] Delay accounting: Initialization References: <43796596.2010908@watson.ibm.com> <20051114202017.6f8c0327.akpm@osdl.org> <17274.34333.348600.111728@wombat.chubb.wattle.id.au> In-Reply-To: <17274.34333.348600.111728@wombat.chubb.wattle.id.au> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1324 Lines: 41 Peter Chubb wrote: >>>>>>"Andrew" == Andrew Morton writes: > > > Andrew> Shailabh Nagar wrote: > >>> + *ts = sched_clock(); > > > Andrew> I'm not sure that it's kosher to use sched_clock() for > Andrew> fine-grained timestamping like this. Ingo had issues with it > Andrew> last time this happened? > > It wasn't Ingo, it was Andi Kleen... for my Microstate Accounting > patches, which do very similar things to Shailabh's patchsetm, but > using /proc and a system call instead (following Solaris's lead) > Were these the comments from Andi to which you refer: http://www.uwsg.indiana.edu/hypermail/linux/kernel/0503.1/1237.html The objections to microstate overhead seemed to stem from the syscall overhead, not use of sched_clock() per se. Andi, Ingo, Are there problems with using sched_clock()for timestamping if one is prepared to live with them not necessarily being nanosecond accurate ? I'm trying to search the archives etc. but if you can respond with any quick comments, that'd be very helpful. Thanks, Shailabh - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/