From mboxrd@z Thu Jan 1 00:00:00 1970 From: 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> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: jeremy-TSDbQ3PG+2Y@public.gmane.org, avi-i/T1Zxg06OZWk0Htik3J/w@public.gmane.org, kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, Glauber de Oliveira Costa , Glauber de Oliveira Costa , --cc-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org To: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Return-path: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: kvm.vger.kernel.org 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 ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/