From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Tue, 24 Oct 2006 18:49:46 +0100 (BST) Received: from localhost.localdomain ([127.0.0.1]:32443 "EHLO dl5rb.ham-radio-op.net") by ftp.linux-mips.org with ESMTP id S20039761AbWJXRto (ORCPT ); Tue, 24 Oct 2006 18:49:44 +0100 Received: from denk.linux-mips.net (denk.linux-mips.net [127.0.0.1]) by dl5rb.ham-radio-op.net (8.13.7/8.13.7) with ESMTP id k9OHo6oW025312; Tue, 24 Oct 2006 18:50:07 +0100 Received: (from ralf@localhost) by denk.linux-mips.net (8.13.7/8.13.7/Submit) id k9OHo4EH025291; Tue, 24 Oct 2006 18:50:04 +0100 Date: Tue, 24 Oct 2006 18:50:04 +0100 From: Ralf Baechle To: Atsushi Nemoto Cc: creideiki+linux-mips@ferretporn.se, linux-mips@linux-mips.org Subject: Re: Extreme system overhead on large IP27 Message-ID: <20061024175004.GA24211@linux-mips.org> References: <20061024140614.GB27800@linux-mips.org> <6285.136.163.203.3.1161704681.squirrel@www.ferretporn.se> <20061024155045.GA28355@linux-mips.org> <20061025.023428.45176894.anemo@mba.ocn.ne.jp> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20061025.023428.45176894.anemo@mba.ocn.ne.jp> User-Agent: Mutt/1.4.2.1i Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 13093 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: ralf@linux-mips.org Precedence: bulk X-list: linux-mips On Wed, Oct 25, 2006 at 02:34:28AM +0900, Atsushi Nemoto wrote: > Date: Wed, 25 Oct 2006 02:34:28 +0900 (JST) > To: ralf@linux-mips.org > Cc: creideiki+linux-mips@ferretporn.se, linux-mips@linux-mips.org > Subject: Re: Extreme system overhead on large IP27 > From: Atsushi Nemoto > Content-Type: Text/Plain; charset=us-ascii > > On Tue, 24 Oct 2006 16:50:45 +0100, Ralf Baechle wrote: > > > 2. Timekeeping is broken. The clock in /proc/driver/rtc seems correct, but > > > the system clock advances at about 1/16 of real time. > > > > This one was caused by changeset ebca9aafa9bd5086d9f310205a8e30e225c5a5a6 > > which apparently wasn't quite ripe. You can work around it by > > revoking this changeset for now. The time damage affects other systems > > as well ... > > Now I'm looking my patch again but still can not find any problem... > > One question: > > > # zcat /proc/config.gz | grep HZ | grep -v ^# > > CONFIG_HZ_250=y > > CONFIG_SYS_SUPPORTS_ARBIT_HZ=y > > CONFIG_HZ=250 > > IP27 really supports HZ=250 ? Arbitrary frequency actually. The timer used is the HUB timer which is running at 800ns afair. It's like 53 bits or so. There is also a compare register so it's somewhat similar to the cop0 counter / compare timer. Ralf