Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 17 Sep 2002 17:19:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 17 Sep 2002 17:19:59 -0400 Received: from pc1-cwma1-5-cust128.swa.cable.ntl.com ([80.5.120.128]:761 "EHLO irongate.swansea.linux.org.uk") by vger.kernel.org with ESMTP id ; Tue, 17 Sep 2002 17:19:58 -0400 Subject: Re: do_gettimeofday vs. rdtsc in the scheduler From: Alan Cox To: "David S. Miller" Cc: ak@suse.de, linux-kernel@vger.kernel.org, johnstul@us.ibm.com, anton.wilson@camotion.com In-Reply-To: <20020917.135451.49037528.davem@redhat.com> References: <1032294559.22815.180.camel@cog.suse.lists.linux.kernel> <20020917.133933.69057655.davem@redhat.com.suse.lists.linux.kernel> <20020917.135451.49037528.davem@redhat.com> Content-Type: text/plain Content-Transfer-Encoding: 7bit X-Mailer: Ximian Evolution 1.0.8 (1.0.8-10) Date: 17 Sep 2002 22:28:12 +0100 Message-Id: <1032298092.20498.21.camel@irongate.swansea.linux.org.uk> Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 786 Lines: 17 On Tue, 2002-09-17 at 21:54, David S. Miller wrote: > The cpu gets a bus clock input, so the system tick should be processor > local as much as TSC is. > > It's boggling that this is being messed up so much. I can't believe > Sun got something incredibly right (Ultra-III has a system tick) :-) A bus clock - but things like the x440 have more than one bus clock. Its NUMA. Also the bus clock and rdtsc clock are different - rdtsc is dependant on the multiplier. Shove a celeron 300 and a celeron 450 in a BP6 board with tsc on and enjoy - 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/