Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753256AbXJ2WK1 (ORCPT ); Mon, 29 Oct 2007 18:10:27 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751803AbXJ2WKO (ORCPT ); Mon, 29 Oct 2007 18:10:14 -0400 Received: from mx1.redhat.com ([66.187.233.31]:37638 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751558AbXJ2WKN (ORCPT ); Mon, 29 Oct 2007 18:10:13 -0400 From: Glauber de Oliveira Costa To: linux-kernel@vger.kernel.org Cc: tglx@linutronix.de, rusty@rustcorp.com.au, jeremy@goop.org, --cc@redhat.com, mingo@elte.hu, avi@quramnet.com, kvm-devel@lists.sourceforge.net, Glauber de Oliveira Costa , Glauber de Oliveira Costa Subject: [PATCH] raise tsc clocksource rating Date: Mon, 29 Oct 2007 20:10:09 -0300 Message-Id: <11936994092607-git-send-email-gcosta@redhat.com> X-Mailer: git-send-email 1.5.0.6 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2262 Lines: 66 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 --- 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/