Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 9 Jan 2002 01:42:04 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 9 Jan 2002 01:41:53 -0500 Received: from w147.z064001233.sjc-ca.dsl.cnc.net ([64.1.233.147]:34757 "EHLO funky.gghcwest.COM") by vger.kernel.org with ESMTP id ; Wed, 9 Jan 2002 01:41:44 -0500 Date: Tue, 8 Jan 2002 22:40:36 -0800 (PST) From: "Jeffrey W. Baker" X-X-Sender: To: Brian cc: Subject: Re: [patch] O(1) scheduler, -D1, 2.5.2-pre9, 2.4.17 In-Reply-To: <0GPN00CMLRC7U8@mtaout45-01.icomcast.net> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 9 Jan 2002, Brian wrote: > Can this be correct? > > Intuitively, I would expect several CPUs hammering away at the compile to > finish faster than one. Given these numbers, I would have to conclude > that is not just wrong, but absolutely wrong. Compile time increases > linearly with the number of jobs, regardless of the number of CPUs. > > What would cause this? Severe memory bottlenecks? Mike ran make -j 8 which means 8 compiler processes for each "# Makes" in the table. Thus, the first row has 8 parallel processes on a 2-way and the last row has 48 processes on an 8-way. The best ratio is 8 processes on an 8-way which not incidentally also has the lowest time: 57 seconds. -jwb > > -- Brian > > On Tuesday 08 January 2002 10:39 pm, Mike Kravetz wrote: > > -------------------------------------------------------------------- > > mkbench - Time how long it takes to compile the kernel. > > We use 'make -j 8' and increase the number of makes run > > in parallel. Result is average build time in seconds. > > Lower is better. > > -------------------------------------------------------------------- > > # CPUs # Makes Vanilla O(1) haMQ > > -------------------------------------------------------------------- > > 2 1 188 192 184 > > 2 2 366 372 362 > > 2 4 730 742 600 > > 2 6 1096 1112 853 > > 4 1 102 101 95 > > 4 2 196 198 186 > > 4 4 384 386 374 > > 4 6 576 579 487 > > 8 1 58 57 58 > > 8 2 109 108 105 > > 8 4 209 213 186 > > 8 6 309 312 280 > - > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/