From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from hera.kernel.org (hera.kernel.org [209.128.68.125]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTP id C2D9F681E8 for ; Thu, 8 Sep 2005 11:42:15 +1000 (EST) Date: Wed, 7 Sep 2005 22:04:28 -0300 From: Marcelo Tosatti To: Tom Rini Message-ID: <20050908010428.GC8882@dmt.cnet> References: <20050826213144.GE5541@smtp.west.cox.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20050826213144.GE5541@smtp.west.cox.net> Cc: Andrew Morton , linuxppc-dev@ozlabs.org, Kumar Gala Subject: Re: [PATCH] ppc32: add CONFIG_HZ List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Fri, Aug 26, 2005 at 02:31:44PM -0700, Tom Rini wrote: > On Fri, Aug 26, 2005 at 04:13:04PM -0400, Dan Malek wrote: > > > > On Aug 26, 2005, at 3:15 PM, Kumar Gala wrote: > > > > >While ppc32 has the CONFIG_HZ Kconfig option, it wasnt actually being > > >used. Connect it up and set all platforms to 250Hz. This pretty much > > >mimics the ppc64 patch from Anton Blanchard. > > > > Why do we keep cranking up this clock frequency? Do we really need > > it running that fast? Is it time for someone with RTOS experience to > > implement a real scheduled clock queue in Linux instead of just > > wasting interrupts decrementing a counter waiting for the next > > event to expire? :-) If the user "ticks" are still 100 Hz, don't we > > need > > something that is an integer multiple of that for at least an attempt > > at getting it close to what a user would request? > > So 250 is supposed to be the best choice of power vs latency and such. > But hey, there's nothing stopping us from setting all of the embedded > configs back down to 100 :) Yep. Kumar, can you please change your patch to make CONFIG_8xx use 100Hz? There was a significant performance increase from doing that (vs 1000Hz) on a 48Mhz 8xx with small cache.