From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755275Ab0C2Krx (ORCPT ); Mon, 29 Mar 2010 06:47:53 -0400 Received: from one.firstfloor.org ([213.235.205.2]:41132 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755168Ab0C2Krj (ORCPT ); Mon, 29 Mar 2010 06:47:39 -0400 To: Hidetoshi Seto Cc: tglx@linutronix.de, linux-kernel@vger.kernel.org, torvalds@osdl.org Subject: Re: [PATCH] Allow Intel platforms to declare unsynchronized TSC to kernel From: Andi Kleen References: <20100324053257.GA4088@basil.fritz.box> <87zl1r7eod.fsf@basil.nowhere.org> <4BB07636.7010708@jp.fujitsu.com> Date: Mon, 29 Mar 2010 12:47:34 +0200 In-Reply-To: <4BB07636.7010708@jp.fujitsu.com> (Hidetoshi Seto's message of "Mon, 29 Mar 2010 18:43:18 +0900") Message-ID: <87oci776bd.fsf@basil.nowhere.org> User-Agent: Gnus/5.1008 (Gnus v5.10.8) Emacs/22.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hidetoshi Seto writes: > (2010/03/29 16:46), Andi Kleen wrote: >> Andi Kleen writes: >> >>> Allow Intel platforms to declare unsynchronized TSC to kernel >>> >>> [This came out of a private discussion with Linus last week] >> >> Ping? Please review this patch. >> >> -Andi > > Does "constant" implicitly means "synchronized"? Yes it does for the CPUID bit. > Following commit tells us that there could be > "constant-but-unsynchronized TSC": > 6c56ccecf05fafe100ab4ea94f6fccbf5ff00db7 >> So, reenable TSC sync test even on constant and non-stop TSC systems. First the platform is supposed to clear in this case and when it doesn't the later check catches it anyways. BTW all the things you're mentioning are not actually changed by my patch. In this regard it behaves the same as before. I don't think the patch description has to describe things it does not change or be a general tutorial on TSCs. -Andi -- ak@linux.intel.com -- Speaking for myself only.