From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264910AbTLPFTp (ORCPT ); Tue, 16 Dec 2003 00:19:45 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264948AbTLPFTp (ORCPT ); Tue, 16 Dec 2003 00:19:45 -0500 Received: from host3.steam.com ([69.36.241.230]:59857 "EHLO gaz.sfgoth.com") by vger.kernel.org with ESMTP id S264910AbTLPFTo (ORCPT ); Tue, 16 Dec 2003 00:19:44 -0500 Date: Mon, 15 Dec 2003 21:20:34 -0800 From: Mitchell Blank Jr To: john stultz Cc: Linux Kernel Subject: Re: Increasing HZ (patch for HZ > 1000) Message-ID: <20031216052034.GI70731@gaz.sfgoth.com> References: <1071126929.5149.24.camel@idefix.homelinux.org> <1293500000.1071127099@[10.10.2.4]> <20031212220853.GA314@elf.ucw.cz> <1071269849.4182.14.camel@idefix.homelinux.org> <20031212234028.GA541@elf.ucw.cz> <1071543853.989.183.camel@cog.beaverton.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1071543853.989.183.camel@cog.beaverton.ibm.com> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org john stultz wrote: > Indeed, with all the trouble HZ==1000 has caused, I'm thinking that > playing w/ HZ at 10k and 10 would be good stress tests for the time > subsystem. I think setting HZ much lower than 100 might break some drivers that do things like: timeout = jiffies + (HZ / 50); Not sure if any of the common drivers have this problem but be on the lookout for it if you want to try running w/ really low HZ. I suppose there should really be a "FRACTION_OF_SECOND()" macro or something that always returns >0 for specifying these really short delays. -Mitch