Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1945989AbWANCft (ORCPT ); Fri, 13 Jan 2006 21:35:49 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1945986AbWANCft (ORCPT ); Fri, 13 Jan 2006 21:35:49 -0500 Received: from ms-smtp-04.nyroc.rr.com ([24.24.2.58]:28342 "EHLO ms-smtp-04.nyroc.rr.com") by vger.kernel.org with ESMTP id S1945987AbWANCfs (ORCPT ); Fri, 13 Jan 2006 21:35:48 -0500 Subject: RE: Dual core Athlons and unsynced TSCs From: Steven Rostedt To: john stultz Cc: Lee Revell , Thomas Gleixner , Ingo Molnar , Roger Heflin , "'linux-kernel'" In-Reply-To: <1137203402.11300.41.camel@cog.beaverton.ibm.com> References: <1137168254.7241.32.camel@localhost.localdomain> <1137174463.15108.4.camel@mindpipe> <1137174848.15108.11.camel@mindpipe> <1137178506.15108.38.camel@mindpipe> <1137182991.8283.7.camel@localhost.localdomain> <1137198221.11300.21.camel@cog.beaverton.ibm.com> <1137201012.6727.1.camel@localhost.localdomain> <1137201250.1408.39.camel@mindpipe> <1137201821.11300.30.camel@cog.beaverton.ibm.com> <1137202039.1408.42.camel@mindpipe> <1137202773.11300.37.camel@cog.beaverton.ibm.com> <1137203402.11300.41.camel@cog.beaverton.ibm.com> Content-Type: text/plain Date: Fri, 13 Jan 2006 21:34:52 -0500 Message-Id: <1137206092.7150.2.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.2.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1382 Lines: 50 On Fri, 2006-01-13 at 17:50 -0800, john stultz wrote: > On Fri, 2006-01-13 at 20:43 -0500, Steven Rostedt wrote: > > On Fri, 13 Jan 2006, john stultz wrote: > > > > > > > > This is as I understand it: > > > > > > With 2.6.15 on x86-64: > > > If available, alternate timesources (HPET, ACPI PM) will be used if > > > available on AMD SMP systems. (clock= is i386 only) > > > > Hmm, should I boot without the clock= to prove this? > > Feel free. That or grep the x86-64 time.c code. > > Look for: > time.c: Using PM based timekeeping. > > To verify the timesource selection. So much for not looking at code! I uploaded yet another version of http://www.kihontech.com/tests/rt/monotonic.c that now also tests the tsc too, to see if it goes backwards. If it does, then it prints (only once) that fact and continues testing the gettime function. So this proves that the tsc does go back and the gettime still is working. $ ./monotonic main program pid=7137 hello from thread 0! hello from thread 4! last tsc is 4389431102233 this tsc is 4389429636684 hello from thread 1! hello from thread 2! hello from thread 3! -- Steve - 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/