Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758418AbZF2JPw (ORCPT ); Mon, 29 Jun 2009 05:15:52 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752873AbZF2JPn (ORCPT ); Mon, 29 Jun 2009 05:15:43 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:39470 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751828AbZF2JPn (ORCPT ); Mon, 29 Jun 2009 05:15:43 -0400 Date: Mon, 29 Jun 2009 11:15:28 +0200 From: Ingo Molnar To: Luming Yu Cc: Arjan van de Ven , LKML , suresh.b.siddha@intel.com, venkatesh.pallipadi@intel.com, Thomas Gleixner , "H. Peter Anvin" Subject: Re: [RFC patch] Use IPI_shortcut for lapic timer broadcast Message-ID: <20090629091528.GB9724@elte.hu> References: <3877989d0906282347i311eb14bp80a7c80878219c31@mail.gmail.com> <20090629072047.GB20225@elte.hu> <3877989d0906290104q11a767b6qcc1acc4c2d1feba6@mail.gmail.com> <20090629081615.GB571@elte.hu> <3877989d0906290121l15705d2cn72e4c49dd96ed950@mail.gmail.com> <20090629083035.GA4017@elte.hu> <3877989d0906290143y3b5306f4s4a990ecbfbfc49b6@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3877989d0906290143y3b5306f4s4a990ecbfbfc49b6@mail.gmail.com> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.5 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 590 Lines: 16 * Luming Yu wrote: > Please note this is deep-C-state related. C state does add extra > latency.. but I don't know how much... ok, so if each of the CPUs has to be brought out of deep-C and with each one 50-100 usecs a pop one could see the total time taking more than 1000 usecs. That would explain the hang. Ingo -- 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/