Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754551Ab1DDLEA (ORCPT ); Mon, 4 Apr 2011 07:04:00 -0400 Received: from service87.mimecast.com ([94.185.240.25]:45744 "HELO service87.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751741Ab1DDLD7 convert rfc822-to-8bit (ORCPT ); Mon, 4 Apr 2011 07:03:59 -0400 Subject: Re: [GIT PULL] omap changes for v2.6.39 merge window From: Catalin Marinas To: Arnd Bergmann Cc: Russell King - ARM Linux , Nicolas Pitre , Detlef Vollmann , Ingo Molnar , david@lang.hm, Tony Lindgren , lkml , "H. Peter Anvin" , David Brown , linux-omap@vger.kernel.org, Linus Torvalds , Thomas Gleixner , linux-arm-kernel@lists.infradead.org In-Reply-To: <201104040259.26601.arnd@arndb.de> References: <201104031726.37420.arnd@arndb.de> <20110403160324.GA8050@n2100.arm.linux.org.uk> <201104040259.26601.arnd@arndb.de> Organization: ARM Limited Date: Mon, 04 Apr 2011 12:03:42 +0100 Message-ID: <1301915022.15819.28.camel@e102109-lin.cambridge.arm.com> Mime-Version: 1.0 X-Mailer: Evolution 2.28.1 X-OriginalArrivalTime: 04 Apr 2011 11:03:45.0507 (UTC) FILETIME=[F7799B30:01CBF2B7] X-MC-Unique: 111040412035103401 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1196 Lines: 27 On Mon, 2011-04-04 at 01:59 +0100, Arnd Bergmann wrote: > On Sunday 03 April 2011, Russell King - ARM Linux wrote: > > Then there's those which change the cs->read function pointer at runtime, ... > > and those which share that pointer with their sched_clock() implementation. > > Abstracting sched_clock() to be run-time selected is something that > needs to be taken care of. Maybe we could have a generic sched_clock > implementation that is written on top of clocksource instead of jiffies, > and always select that on architectures that have a decent clocksource. On Cortex-A15 with the virtualisation extensions and architected timers the clocksource is implemented using a physical counter (as we want wall-clock timing). But for sched_clock() we may want to use a virtual counter (which is basically an offset from the physical one, set by the hypervisor during guest OS switching). Marc already posted some patches for this. -- Catalin -- 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/