Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754149AbZG1TZ3 (ORCPT ); Tue, 28 Jul 2009 15:25:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753514AbZG1TZ2 (ORCPT ); Tue, 28 Jul 2009 15:25:28 -0400 Received: from vms173001pub.verizon.net ([206.46.173.1]:21004 "EHLO vms173001pub.verizon.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752730AbZG1TZ1 (ORCPT ); Tue, 28 Jul 2009 15:25:27 -0400 Date: Tue, 28 Jul 2009 15:25:12 -0400 (EDT) From: Len Brown X-X-Sender: lenb@localhost.localdomain To: Corrado Zoccolo Cc: "Zhang, Yanmin" , Andreas Mohr , LKML , linux-acpi@vger.kernel.org Subject: Re: Dynamic configure max_cstate In-reply-to: <4e5e476b0907280020x242d9ef7gfa05c3d7b66f941f@mail.gmail.com> Message-id: References: <20090727073338.GA12669@rhlx01.hs-esslingen.de> <1248748935.2560.669.camel@ymzhang> <4e5e476b0907280020x242d9ef7gfa05c3d7b66f941f@mail.gmail.com> User-Agent: Alpine 2.00 (LFD 1167 2008-08-23) 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 Content-Length: 582 Lines: 16 > Entering a deep C state can cause strange things to timers: some of > them, especially tsc, become unreliable. The Nehalem family CPU has a non-stop constant-frequency TSC. The measurements that Yanmin quotes show that the TSC is the lowest overhead timesource in the system. thanks, Len Brown, Intel Open Source Technology Center -- 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/