From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1765179AbXGSVGy (ORCPT ); Thu, 19 Jul 2007 17:06:54 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1765580AbXGSVGm (ORCPT ); Thu, 19 Jul 2007 17:06:42 -0400 Received: from mtagate8.de.ibm.com ([195.212.29.157]:30290 "EHLO mtagate8.de.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1762480AbXGSVGk (ORCPT ); Thu, 19 Jul 2007 17:06:40 -0400 Subject: Re: [PATCH] virtual sched_clock() for s390 From: Jan Glauber To: Ingo Molnar Cc: Jeremy Fitzhardinge , LKML , vatsa@linux.vnet.ibm.com, mschwid2@linux.vnet.ibm.com, efault@gmx.de, dmitry.adamushko@gmail.com, paulus@samba.org, anton@samba.org In-Reply-To: <20070719193840.GA29523@elte.hu> References: <1184842661.6546.14.camel@localhost.localdomain> <469F8342.7060000@goop.org> <20070719160025.GA31815@elte.hu> <1184872821.5516.10.camel@localhost.localdomain> <20070719193840.GA29523@elte.hu> Content-Type: text/plain Date: Thu, 19 Jul 2007 21:07:03 +0000 Message-Id: <1184879223.5516.45.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.6.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2007-07-19 at 21:38 +0200, Ingo Molnar wrote: > * Jan Glauber wrote: > > > > still, CFS needs time measurement across idle periods as well, for > > > another purpose: to be able to do precise task statistics for /proc. > > > (for top, ps, etc.) So it's still true that sched_clock() should > > > include idle periods too. > > > > I'm not sure, s390 already has an implemetation for precise accounting > > in the architecture code, does CFS also improve accounting data? > > what kind of precise accounting does s390 have in the architecture code? > CFS changes task (and load) accounting to be sched_clock() driven in > essence. s390 has per-process accounting that is aware of virtual cpu time, implemented in arch/s390/kernel/time.c: account_ticks() and arch/s390/kernel/vtime.c: account_*_vtime(). Timestamps are taken in entry.S for system calls, interrupts and other system entries and are accounted later, we don't call update_process_times(). Jan > Ingo > - > 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/