From mboxrd@z Thu Jan 1 00:00:00 1970 From: Benjamin Herrenschmidt Subject: Re: [patch 0/4] [RFC] true vs. system idle cputime Date: Thu, 16 Oct 2008 07:56:30 +1100 Message-ID: <1224104190.8157.473.camel@pasglop> References: <20081008161958.767142939@de.ibm.com> <1224079316.16990.28.camel@localhost> Reply-To: benh@kernel.crashing.org Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: Received: from gate.crashing.org ([63.228.1.57]:33902 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752599AbYJOU54 (ORCPT ); Wed, 15 Oct 2008 16:57:56 -0400 In-Reply-To: <1224079316.16990.28.camel@localhost> Sender: linux-arch-owner@vger.kernel.org List-ID: To: schwidefsky@de.ibm.com Cc: linux-arch@vger.kernel.org, Heiko Carstens , Paul Mackerras , Hidetoshi Seto , Tony Luck , Jeremy Fitzhardinge , Chris Wright , Michael Neuling On Wed, 2008-10-15 at 16:01 +0200, Martin Schwidefsky wrote: > > There is one change in patch #2 that might require a change on powerpc > > and/or ia64. The generic TICK_ONESHOT/NO_HZ code calculates the number > > of ticks spent with a disabled HZ timer and accounts this as idle time. > > For a configuration for VIRT_CPU_ACCOUNTING=y this is horribly wrong. > > Either you have precise accounting or you don't. Patch #2 just removes > > the calculation for VIRT_CPU_ACCOUNTING=y. The architectures which support > > precise accounting have to deal with it on their own. This is where the > > powerpc and ia64 maintainer come into play. Would you look at patch #2 > > please ? > > > > To make it clearer what happens in tick_nohz_restart_sched_tick I've added > > a new function account_idle_ticks(). And for good measure another one named > > account_steal_ticks() for xen where "interesting" things have been done > > with the account_steal_time interface. > > Any news about powerpc? Do these patches break anything or does it work? I didn't have a chance to look at it yet. I'll try to get that looked at today. Cheers, Ben.