Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754554AbZAFUev (ORCPT ); Tue, 6 Jan 2009 15:34:51 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751915AbZAFUel (ORCPT ); Tue, 6 Jan 2009 15:34:41 -0500 Received: from mga02.intel.com ([134.134.136.20]:48594 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751910AbZAFUek convert rfc822-to-8bit (ORCPT ); Tue, 6 Jan 2009 15:34:40 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.37,221,1231142400"; d="scan'208";a="479422328" From: "Luck, Tony" To: Robin Holt CC: Dimitri Sivanich , "linux-ia64@vger.kernel.org" , Greg KH , "linux-kernel@vger.kernel.org" , Peter Zijlstra , Gregory Haskins , Nick Piggin , Tony Luck Date: Tue, 6 Jan 2009 12:34:06 -0800 Subject: RE: [PATCH] configure HAVE_UNSTABLE_SCHED_CLOCK for SGI_SN systems Thread-Topic: [PATCH] configure HAVE_UNSTABLE_SCHED_CLOCK for SGI_SN systems Thread-Index: AclwPC5k6IBw6MW9Te2lgpXylAJfvQAANFfg Message-ID: <57C9024A16AD2D4C97DC78E552063EA35CB955B4@orsmsx505.amr.corp.intel.com> References: <20090106162741.GA7991@sgi.com> <57C9024A16AD2D4C97DC78E552063EA35CB95575@orsmsx505.amr.corp.intel.com> <20090106201950.GA3850@sgi.com> In-Reply-To: <20090106201950.GA3850@sgi.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1064 Lines: 26 > > All ia64 systems are potentially affected ... but perhaps you might > > never see the problem on most because the itc clocks are synced as close > > as s/w can get them when cpus are brought on line. > > Do you want Dimitri to resubmit with this set for all IA64 or leave it > as is? I'd like to understand the impact of turning on HAVE_UNSTABLE_SCHED_CLOCK It looks like both the i386_defconfig and x86_64_defconfig choose this, so at least ia64 will be hitting the well tested code paths Have the other architectures just not hit this yet? Or do they all have "stable" sched_clock() functions? sched_clock() seemed like such a straightforward thing to begin with. A quick & easy way to measure a time delta ON THE SAME CPU. I'm not at all sure why it has been co-opted for general time measurement. -Tony -- 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/