Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932204Ab0KSUTX (ORCPT ); Fri, 19 Nov 2010 15:19:23 -0500 Received: from canuck.infradead.org ([134.117.69.58]:57251 "EHLO canuck.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932120Ab0KSUTW convert rfc822-to-8bit (ORCPT ); Fri, 19 Nov 2010 15:19:22 -0500 Subject: Re: [patch 0/4] taskstats: Improve cumulative time accounting From: Peter Zijlstra To: Michael Holzheu Cc: Oleg Nesterov , Shailabh Nagar , Andrew Morton , John stultz , Thomas Gleixner , Balbir Singh , Martin Schwidefsky , Heiko Carstens , Roland McGrath , linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org In-Reply-To: <20101119201108.269346583@linux.vnet.ibm.com> References: <20101119201108.269346583@linux.vnet.ibm.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT Date: Fri, 19 Nov 2010 21:19:15 +0100 Message-ID: <1290197955.2109.1617.camel@laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.30.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1169 Lines: 24 On Fri, 2010-11-19 at 21:11 +0100, Michael Holzheu wrote: > Due to POSIX POSIX.1-2001, the CPU time of processes is not accounted > to the cumulative time of the parents, if the parents ignore SIGCHLD > or have set SA_NOCLDWAIT. This behaviour has the major drawback that > it is not possible to calculate all consumed CPU time of a system by > looking at the current tasks. CPU time can be lost. > > To solve this problem, this patch set duplicates the cumulative accounting > data in the signal_struct. In the second set (cdata_acct) the complete > cumulative resource counters are stored. The new cumulative CPU time (utime > and stime) is then exported via the taskstats interface. Maybe this has been treated earlier in the threads and I missed it, but the obvious solution doesn't get mentioned: What would break if we violate this silly POSIX rule and account time of childs regardless of SIGCHLD/SA_NOCLDWAIT? -- 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/