Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756560AbXH2RU0 (ORCPT ); Wed, 29 Aug 2007 13:20:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751130AbXH2RUR (ORCPT ); Wed, 29 Aug 2007 13:20:17 -0400 Received: from smtp2.linux-foundation.org ([207.189.120.14]:45444 "EHLO smtp2.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751443AbXH2RUQ (ORCPT ); Wed, 29 Aug 2007 13:20:16 -0400 Date: Wed, 29 Aug 2007 10:20:05 -0700 From: Stephen Hemminger To: Jan Engelhardt Cc: DervishD , Linux-kernel Subject: Re: cpufreq affects traffic control rates Message-ID: <20070829102005.5450723e@freepuppy.rosehill.hemminger.net> In-Reply-To: References: <20070828075155.GG17475@DervishD> <20070828152309.7fe1ce91@freepuppy.rosehill.hemminger.net> Organization: Linux Foundation X-Mailer: Claws Mail 2.10.0 (GTK+ 2.10.14; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1375 Lines: 36 On Wed, 29 Aug 2007 17:26:24 +0200 (CEST) Jan Engelhardt wrote: > > On Aug 28 2007 15:23, Stephen Hemminger wrote: > >> I noticed lately that my traffic control rates were being very slow, > >> about 40% less than expected, and finally spotted the problem: cpufreq. > >> > >> Looks like HTB puts buckets according to the requested rate but > >> assuming that the CPU is running at its default clock or something like > >> that. > >> > >Is the problem configuration of network scheduler clock? In 2.6.20 and earlier, you > >could use CPU cycle counter (later kernels only use time of day). So try > >switching to jiffies or gettimeofday. > > This should not have been removed. CPUs with constant_tsc > could still be used with "CPU cycle counter" method. > > > Jan It was removed because the core clock subsystem now manages the choice of CPU clock correctly and should provide the highest resolution possible on the hardware. Plus a whole bunch of grotty macro code gets removed. And the math handling was more standard/simpler. -- Stephen Hemminger - 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/