Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754321AbXJ2WUu (ORCPT ); Mon, 29 Oct 2007 18:20:50 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751907AbXJ2WUn (ORCPT ); Mon, 29 Oct 2007 18:20:43 -0400 Received: from www.tglx.de ([62.245.132.106]:51870 "EHLO www.tglx.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752410AbXJ2WUn (ORCPT ); Mon, 29 Oct 2007 18:20:43 -0400 Date: Mon, 29 Oct 2007 23:17:38 +0100 (CET) From: Thomas Gleixner To: Glauber de Oliveira Costa cc: LKML , Rusty Russell , Jeremy Fitzhardinge , --cc@redhat.com, Ingo Molnar , avi@quramnet.com, kvm-devel@lists.sourceforge.net, John Stultz Subject: Re: [PATCH] raise tsc clocksource rating In-Reply-To: <11936994092607-git-send-email-gcosta@redhat.com> Message-ID: References: <11936994092607-git-send-email-gcosta@redhat.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2796 Lines: 79 On Mon, 29 Oct 2007, Glauber de Oliveira Costa wrote: CC'ed John and removed glauber@t60.localdomain :) > From: Glauber de Oliveira Costa > > tsc is very good time source (when it does not have drifts, does not > change it's frequency, i.e. when it works), so it should have its rating > raised to a value greater than, or equal 400. > > Since it's being a tendency among paravirt clocksources to use values > around 400, we should declare tsc as even better: So we use 500. > > This patch also touches the comments on clocksource.h, which suggests > that 499 would be a limit on the rating values. > > Signed-off-by: Glauber de Oliveira Costa Acked-by: Thomas Gleixner > --- > arch/x86/kernel/tsc_32.c | 2 +- > arch/x86/kernel/tsc_64.c | 2 +- > include/linux/clocksource.h | 2 +- > 3 files changed, 3 insertions(+), 3 deletions(-) > > diff --git a/arch/x86/kernel/tsc_32.c b/arch/x86/kernel/tsc_32.c > index 9ebc0da..4d91e59 100644 > --- a/arch/x86/kernel/tsc_32.c > +++ b/arch/x86/kernel/tsc_32.c > @@ -280,7 +280,7 @@ static cycle_t read_tsc(void) > > static struct clocksource clocksource_tsc = { > .name = "tsc", > - .rating = 300, > + .rating = 500, > .read = read_tsc, > .mask = CLOCKSOURCE_MASK(64), > .mult = 0, /* to be set */ > diff --git a/arch/x86/kernel/tsc_64.c b/arch/x86/kernel/tsc_64.c > index 9c70af4..4fd5b1b 100644 > --- a/arch/x86/kernel/tsc_64.c > +++ b/arch/x86/kernel/tsc_64.c > @@ -262,7 +262,7 @@ static cycle_t __vsyscall_fn vread_tsc(void) > > static struct clocksource clocksource_tsc = { > .name = "tsc", > - .rating = 300, > + .rating = 500, > .read = read_tsc, > .mask = CLOCKSOURCE_MASK(64), > .shift = 22, > diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h > index 107787a..5b0aadd 100644 > --- a/include/linux/clocksource.h > +++ b/include/linux/clocksource.h > @@ -39,7 +39,7 @@ struct clocksource; > * A correct and usable clocksource. > * 300-399: Desired. > * A reasonably fast and accurate clocksource. > - * 400-499: Perfect > + * >= 400 : Perfect > * The ideal clocksource. A must-use where > * available. > * @read: returns a cycle value > -- > 1.5.0.6 > > - > 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/ > - 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/