Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Thu, 19 Dec 2002 17:29:34 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Thu, 19 Dec 2002 17:28:06 -0500 Received: from atrey.karlin.mff.cuni.cz ([195.113.31.123]:25356 "EHLO atrey.karlin.mff.cuni.cz") by vger.kernel.org with ESMTP id ; Thu, 19 Dec 2002 17:26:51 -0500 Date: Thu, 19 Dec 2002 23:34:51 +0100 From: Pavel Machek To: "H. Peter Anvin" Cc: Pavel Machek , dean gaudet , Linus Torvalds , Dave Jones , Ingo Molnar , linux-kernel@vger.kernel.org Subject: Re: Intel P6 vs P7 system call performance Message-ID: <20021219223451.GG17941@atrey.karlin.mff.cuni.cz> References:

<20021218235327.GC705@elf.ucw.cz> <3E0245C1.5060902@transmeta.com> <20021219222136.GC17941@atrey.karlin.mff.cuni.cz> <3E0246DE.2010608@transmeta.com> <20021219222614.GE17941@atrey.karlin.mff.cuni.cz> <3E024880.4010802@transmeta.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3E024880.4010802@transmeta.com> User-Agent: Mutt/1.3.28i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 721 Lines: 19 Hi! > > User on cpu1 reads time, communicates it to cpu2, but cpu2 is drifted > > -50ns, so it reads time "before" time reported cpu1. And gets confused. > > > > How can you get that communication to happen in < 50 ns? I'm not sure I can do that, but I'm not sure I can't either. CPUs snoop each other's cache, and that's supposed to be fast... -- Casualities in World Trade Center: ~3k dead inside the building, cryptography in U.S.A. and free speech in Czech Republic. - 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/