Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Thu, 19 Dec 2002 17:12:47 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Thu, 19 Dec 2002 17:11:57 -0500 Received: from neon-gw-l3.transmeta.com ([63.209.4.196]:46600 "EHLO neon-gw.transmeta.com") by vger.kernel.org with ESMTP id convert rfc822-to-8bit; Thu, 19 Dec 2002 17:10:42 -0500 Message-ID: <3E0245C1.5060902@transmeta.com> Date: Thu, 19 Dec 2002 14:18:41 -0800 From: "H. Peter Anvin" Organization: Transmeta Corporation User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.3a) Gecko/20021119 X-Accept-Language: en, sv MIME-Version: 1.0 To: Pavel Machek CC: dean gaudet , Linus Torvalds , Dave Jones , Ingo Molnar , linux-kernel@vger.kernel.org Subject: Re: Intel P6 vs P7 system call performance References:

<20021218235327.GC705@elf.ucw.cz> In-Reply-To: <20021218235327.GC705@elf.ucw.cz> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT X-MIME-Autoconverted: from 8bit to quoted-printable by deepthought.transmeta.com id gBJMIW322825 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 677 Lines: 21 Pavel Machek wrote: >> >>don't many of the multi-CPU problems with tsc go away because you've got a >>per-cpu physical page for the vsyscall? >> >>i.e. per-cpu tsc epoch and scaling can be set on that page. > > Problem is that cpu's can randomly drift +/- 100 clocks or so... Not > nice at all. > ???100 clocks is what... ?50 ns these days? You can't get that kind of accuracy for anything outside the CPU core anyway... -hpa - 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/