From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Fri, 11 Jan 2002 16:19:32 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Fri, 11 Jan 2002 16:19:23 -0500 Received: from gateway-1237.mvista.com ([12.44.186.158]:28155 "EHLO hermes.mvista.com") by vger.kernel.org with ESMTP id ; Fri, 11 Jan 2002 16:19:07 -0500 Message-ID: <3C3F56A0.E1240EE6@mvista.com> Date: Fri, 11 Jan 2002 13:18:24 -0800 From: george anzinger Organization: Monta Vista Software X-Mailer: Mozilla 4.77 [en] (X11; U; Linux 2.2.12-20b i686) X-Accept-Language: en MIME-Version: 1.0 To: Robert Love CC: linux-kernel@vger.kernel.org, kpreempt-tech@lists.sourceforge.net, mingo@elte.hu, torvalds@transmeta.com Subject: Re: [PATCH] Preemptive Kernel for Ingo's O(1) scheduler In-Reply-To: <1010783095.819.61.camel@phantasy> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Robert Love wrote: > > A version of preempt-kernel is now available for Ingo's O(1) scheduler. Great! Well done. > > For 2.5.2-pre11: > ftp://ftp.kernel.org/pub/linux/kernel/people/rml/preempt-kernel/v2.5/preempt-kernel-rml-2.5.2-pre11-1.patch > For 2.4.18-pre3 + sched-O1-H6: > ftp://ftp.kernel.org/pub/linux/kernel/people/rml/preempt-kernel/v2.4/ingo-O1-sched/preempt-kernel-rml-2.4.18-pre3-ingo-1.patch > > Because of changes in load_balance, I suggest not using preempt-kernel > and an additional sched update on 2.5. I'll update as the patches are > merged into 2.5. > > Making the kernel fully preemptible should be synergistic with Ingo's > scheduler with its faster task dispatch time and better RT support. > > Getting the two to play together was not hard, albeit a bit of a pain. > The actually scheduling support is less, due to the simplified schedule > and schedule_tail, although there is added code for making the per-CPU > runqueues preempt-safe. > > Benchmarks: > > 2.5.2-pre11 dbench 16: 24.5364 MB/s > 2.5.2-pre11-preempt dbench 16: 27.5192 MB/s > > 2.5.2-pre11 latencytest: > worst-case latency is 18.7ms with 96% scheduling latency on-time > 2.5.2-pre11-preempt latencytest: > 6ms (<1.5ms in all but disk write) with 99.9% scheduling latency on-time > > 2.5.2-pre11-preempt avg latency is 1.1ms (for an arbitray work-load I > tested with). The obstacle for sub-ms average latency is still the > long-held spinlocks that can be 100ms+. > > Full ChangeLog: > > - make preempt-kernel and Ingo's O(1) scheduler play nicely > > - (2.5 only) more include additions > > - various cleanups and such > > Comments, patches, etc. are appreciated. While it is running stable > here in both SMP and UP on both 2.4 and 2.5, more testing could reveal > problems. Also, some optimization could be done at this point to > hopefully reduce overhead. Enjoy, > > Robert Love -- George george@mvista.com High-res-timers: http://sourceforge.net/projects/high-res-timers/ Real time sched: http://sourceforge.net/projects/rtsched/