From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Thu, 18 Jan 2001 20:24:14 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Thu, 18 Jan 2001 20:24:05 -0500 Received: from gateway.sequent.com ([192.148.1.10]:42923 "EHLO gateway.sequent.com") by vger.kernel.org with ESMTP id ; Thu, 18 Jan 2001 20:23:51 -0500 Date: Thu, 18 Jan 2001 17:23:44 -0800 From: Mike Kravetz To: Andi Kleen Cc: Mark Hahn , linux-kernel@vger.kernel.org Subject: Re: multi-queue scheduler update Message-ID: <20010118172344.I8637@w-mikek.des.sequent.com> In-Reply-To: <20010119012616.D32087@athlon.random> <20010119020852.A6973@gruyere.muc.suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 1.0.1i In-Reply-To: <20010119020852.A6973@gruyere.muc.suse.de>; from ak@suse.de on Fri, Jan 19, 2001 at 02:08:52AM +0100 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jan 19, 2001 at 02:08:52AM +0100, Andi Kleen wrote: > On Thu, Jan 18, 2001 at 08:00:16PM -0500, Mark Hahn wrote: > > > > microseconds/yield > > > > # threads 2.2.16-22 2.4 2.4-multi-queue > > > > ------------ --------- -------- --------------- > > > > 16 18.740 4.603 1.455 > > > > > > I remeber the O(1) scheduler from Davide Libenzi was beating the mainline O(N) > > > > isn't the normal case (as in "The Right Case to optimize") > > where there are close to zero runnable tasks? what realistic/sane > > scenarios have very large numbers of spinning threads? all server > > situations I can think of do not. not volanomark -loopback, surely! > > I think the main point of Mike's patch is decreasing locking and cache line > bouncing overhead of multi cpu scheduling, not optimizing lots of runnable tasks. > > > -Andi Andi is correct. Although the results I posted may seem to indicate we are concentrating on high thread counts, this is really secondary to reducing lock contention within the scheduler. A co-worker down the hall just ran pgbench (a postgresql db) benchmark and saw contention on the runqueue lock at 57%. Now, I know nothing about this benchmark, but it will be interesting to see what happens after applying my patch. -- Mike Kravetz mkravetz@sequent.com IBM Linux Technology Center - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/