From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTP id BC056683A8 for ; Wed, 5 Oct 2005 08:15:07 +1000 (EST) From: Benjamin Herrenschmidt To: Marc In-Reply-To: <200510040814.07188.marvin24@gmx.de> References: <200510040814.07188.marvin24@gmx.de> Content-Type: text/plain Date: Wed, 05 Oct 2005 08:14:54 +1000 Message-Id: <1128464094.6417.31.camel@gaston> Mime-Version: 1.0 Cc: linuxppc-dev@ozlabs.org, linux-kernel@vger.kernel.org Subject: Re: clock skew on B/W G3 List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Tue, 2005-10-04 at 08:14 +0200, Marc wrote: > Hi, > > given that this option causes problems on non i386 systems, may I propose to > mark CONFIG_HZ as broken on these architectures and/or use a default value of > 1000 ? I guess this issue can't be fixed in a sane way until 2.6.14 is out. The problem is indeed in via_calibrate_decr(). This routine works on HZ/100 so it will not do any good with HZ not beeing a multiple of 100. Can you test this patch ? Index: linux-work/arch/ppc/platforms/pmac_time.c =================================================================== --- linux-work.orig/arch/ppc/platforms/pmac_time.c 2005-09-22 14:06:18.000000000 +1000 +++ linux-work/arch/ppc/platforms/pmac_time.c 2005-10-05 08:14:17.000000000 +1000 @@ -195,7 +195,7 @@ ; dend = get_dec(); - tb_ticks_per_jiffy = (dstart - dend) / (6 * (HZ/100)); + tb_ticks_per_jiffy = (dstart - dend) / ((6 * HZ)/100); tb_to_us = mulhwu_scale_factor(dstart - dend, 60000); printk(KERN_INFO "via_calibrate_decr: ticks per jiffy = %u (%u ticks)\n",