From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rusty Russell Subject: Re: [PATCH] raise tsc clocksource rating Date: Tue, 30 Oct 2007 13:39:23 +1100 Message-ID: <200710301339.23628.rusty@rustcorp.com.au> References: <11936994092607-git-send-email-gcosta@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Jeremy Fitzhardinge , avi-i/T1Zxg06OZWk0Htik3J/w@public.gmane.org, kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, John Stultz , LKML , Glauber de Oliveira Costa , --cc-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org To: Thomas Gleixner Return-path: In-Reply-To: Content-Disposition: inline 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 On Tuesday 30 October 2007 09:17:38 Thomas Gleixner wrote: > On Mon, 29 Oct 2007, Glauber de Oliveira Costa wrote: > > CC'ed John and removed glauber-aMxvdZfKFXomYvmMESoHnA@public.gmane.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 > > Acked-by: Thomas Gleixner No. tsc is very good, it's not perfect. If a paravirt clock registers 400 it really means "pick me over the tsc". That's *why* they use > 400: it's in the documentation. Rusty. ------------------------------------------------------------------------- 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/