From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933785AbYEBVsh (ORCPT ); Fri, 2 May 2008 17:48:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756685AbYEBVs2 (ORCPT ); Fri, 2 May 2008 17:48:28 -0400 Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:57945 "EHLO sunset.davemloft.net" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1752521AbYEBVs2 (ORCPT ); Fri, 2 May 2008 17:48:28 -0400 Date: Fri, 02 May 2008 14:48:27 -0700 (PDT) Message-Id: <20080502.144827.158329188.davem@davemloft.net> To: a.p.zijlstra@chello.nl Cc: efault@gmx.de, elendil@planet.nl, parag.warudkar@gmail.com, mingo@elte.hu, linux-kernel@vger.kernel.org, guichaz@yahoo.fr, andi@firstfloor.org Subject: Re: 'global' rq->clock From: David Miller In-Reply-To: <1209758186.6929.18.camel@lappy> References: <200805022053.24779.elendil@planet.nl> <1209756423.4693.8.camel@marge.simson.net> <1209758186.6929.18.camel@lappy> X-Mailer: Mew version 5.2 on Emacs 22.1 / Mule 5.0 (SAKAKI) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Peter Zijlstra Date: Fri, 02 May 2008 21:56:26 +0200 > Ok, the the below would need something that relates tick_timestamp's to > one another.. probably sucks without it.. > > OTOH, Andi said he was working on a fastish global sched_clock() thingy, > Andi got a link to that code? While I'm fine with this kind of stuff being added to constantly cope with x86's joke of a TSC register implementation, it's starting to become an enormous burdon for platforms where the TICK source actually works properly. Heck, on my Niagara2 chips, all 64 cpus use the same physical register for the TICK source, it physically can't get desynchronized :-) So, a way to turn all of this muck off would be much appreciated. I'm happy to test anything on sparc64, and I'm sure the powerpc folks are as well. And I also heard a rumor that Peter has access to a machine with a stable tick source for testing :-)