From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751400AbWCDGuo (ORCPT ); Sat, 4 Mar 2006 01:50:44 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751405AbWCDGuo (ORCPT ); Sat, 4 Mar 2006 01:50:44 -0500 Received: from mail12.syd.optusnet.com.au ([211.29.132.193]:10418 "EHLO mail12.syd.optusnet.com.au") by vger.kernel.org with ESMTP id S1751400AbWCDGuo (ORCPT ); Sat, 4 Mar 2006 01:50:44 -0500 From: Con Kolivas To: Mike Galbraith Subject: Re: [patch 2.6.16-rc5-mm2] sched_cleanup-V17 - task throttling patch 1 of 2 Date: Sat, 4 Mar 2006 17:50:20 +1100 User-Agent: KMail/1.9.1 Cc: "Randy.Dunlap" , pwil3058@bigpond.net.au, linux-kernel@vger.kernel.org, mingo@elte.hu, nickpiggin@yahoo.com.au, kenneth.w.chen@intel.com, akpm@osdl.org References: <1140183903.14128.77.camel@homer> <200603041654.59480.kernel@kolivas.org> <1141455048.9482.13.camel@homer> In-Reply-To: <1141455048.9482.13.camel@homer> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200603041750.21484.kernel@kolivas.org> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Saturday 04 March 2006 17:50, Mike Galbraith wrote: > On Sat, 2006-03-04 at 16:54 +1100, Con Kolivas wrote: > > On Saturday 04 March 2006 16:40, Randy.Dunlap wrote: > > > On Sat, 04 Mar 2006 06:29:47 +0100 Mike Galbraith wrote: > > > > On Sat, 2006-03-04 at 16:24 +1100, Con Kolivas wrote: > > > > > On Saturday 04 March 2006 16:20, Mike Galbraith wrote: > > > > > > On Sat, 2006-03-04 at 13:33 +1100, Peter Williams wrote: > > > > > > > > include/linux/sched.h | 3 - > > > > > > > > kernel/sched.c | 136 > > > > > > > > +++++++++++++++++++++++++++++--------------------- 2 files > > > > > > > > changed, 82 insertions(+), 57 deletions(-) > > > > > > > > > > > > > > > > --- linux-2.6.16-rc5-mm2/include/linux/sched.h.org 2006-03-01 > > > > > > > > 15:06:22.000000000 +0100 +++ > > > > > > > > linux-2.6.16-rc5-mm2/include/linux/sched.h 2006-03-02 > > > > > > > > 08:33:12.000000000 +0100 @@ -720,7 +720,8 @@ > > > > > > > > > > > > > > > > unsigned long policy; > > > > > > > > cpumask_t cpus_allowed; > > > > > > > > - unsigned int time_slice, first_time_slice; > > > > > > > > + int time_slice; > > > > > > > > > > > > > > Can you guarantee that int is big enough to hold a time slice > > > > > > > in nanoseconds on all systems? I think that you'll need more > > > > > > > than 16 bits. > > > > > > > > > > > > Nope, that's a big fat bug. > > > > > > > > > > Most ints are 32bit anyway, but even a 32 bit unsigned int > > > > > overflows with nanoseconds at 4.2 seconds. A signed one at about > > > > > half that. Our timeslices are never that large, but then int isn't > > > > > always 32bit either. > > > > > > > > Yup. I just didn't realize that there were 16 bit integers out > > > > there. > > > > > > LDD 3rd ed. doesn't know about them either. Same for me. > > > > Alright I made that up, but it might not be one day :P > > Well Fudgecicles. Now you guys have gotten me aaaaall confused. Are > there cpus out there (in generic linux land) that have 16 bit integers > or not? 16 bit integers existing in a 32 bit cpu OS seems like an alien > concept to me, but I'm not a twisted cpu designer... I'll just go with > the flow ;-) All supported architectures on linux currently use 32bits for int. That should give you 2.1 seconds in nanoseconds. Sorry my legacy of remembering when ints were 8 bits coloured me. Cheers, Con