From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261358AbVGONM5 (ORCPT ); Fri, 15 Jul 2005 09:12:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261364AbVGONM5 (ORCPT ); Fri, 15 Jul 2005 09:12:57 -0400 Received: from zproxy.gmail.com ([64.233.162.193]:12655 "EHLO zproxy.gmail.com") by vger.kernel.org with ESMTP id S261358AbVGONM4 convert rfc822-to-8bit (ORCPT ); Fri, 15 Jul 2005 09:12:56 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:reply-to:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=IyH1d7C3YWB+Mazsy2SsgJDPA0GFo23NaLgwbOjnKnQl1DiMsd9HH6XfRAzSUWOCvn1PeAg+4putWK8y1a5CTkIc8COAgipJRA1o1cEOtbQE8YK1nZpXiCCli/UXnET82iRu90ByfSxpoKaEgrK7A8jNQsBRixCLXhRh0i4Y9MQ= Message-ID: <9a874849050715061247ab4fd8@mail.gmail.com> Date: Fri, 15 Jul 2005 15:12:51 +0200 From: Jesper Juhl Reply-To: Jesper Juhl To: Linus Torvalds Subject: Re: [PATCH] i386: Selectable Frequency of the Timer Interrupt Cc: Lee Revell , Chris Wedgwood , Andrew Morton , "Brown, Len" , dtor_core@ameritech.net, vojtech@suse.cz, david.lang@digitalinsight.com, davidsen@tmr.com, kernel@kolivas.org, linux-kernel@vger.kernel.org, mbligh@mbligh.org, diegocg@gmail.com, azarah@nosferatu.za.org, christoph@lameter.com In-Reply-To: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT Content-Disposition: inline References: <42D3E852.5060704@mvista.com> <1121286258.4435.98.camel@mindpipe> <20050713134857.354e697c.akpm@osdl.org> <20050713211650.GA12127@taniwha.stupidest.org> <9a874849050714170465c979c3@mail.gmail.com> <1121386505.4535.98.camel@mindpipe> <42D731A4.40504@gmail.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On 7/15/05, Linus Torvalds wrote: > > On Fri, 15 Jul 2005, Jesper Juhl wrote: > > > > It's buggy, that I know. setting kernel_hz (the new boot parameter) to > > 250 causes my system clock to run at something like 4-5 times normal > > speed > > 4 times normal. You don't actually make the timer interrupt happen at > 250Hz, so the timer will be programmed to run at the full 1kHz. > Right, that's the basic problem. I increase jiffies at a higher rate but didn't slow the timer interrupt down at the same time. > You also need to actually change the LATCH define (in > include/linux/jiffies.h) to take this into account (there might be > something else too). > [...] > and you might be getting closer. > > Of course, you need to make sure that LATCH is used only after > jiffies_increment is set up. See "setup_pit_timer(void)" in > arch/i386/kernel/timers/timer_pit.c for more details. > Thank you for all the pointers and hints. This is a new area of code for me, so I'll need some time to poke around - the above helps a lot. Unfortunately I won't have any time to work on this today, but I'll see if I can get a working implementation together tomorrow. -- Jesper Juhl Don't top-post http://www.catb.org/~esr/jargon/html/T/top-post.html Plain text mails only, please http://www.expita.com/nomime.html