From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 6 Mar 2001 19:08:19 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 6 Mar 2001 19:08:09 -0500 Received: from jalon.able.es ([212.97.163.2]:31945 "EHLO jalon.able.es") by vger.kernel.org with ESMTP id ; Tue, 6 Mar 2001 19:07:57 -0500 Date: Wed, 7 Mar 2001 01:07:34 +0100 From: "J . A . Magallon" To: Ying Chen Cc: linux-kernel@vger.kernel.org Subject: Re: threads Message-ID: <20010307010734.C1132@werewolf.able.es> In-Reply-To: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT In-Reply-To: ; from yingchenb@hotmail.com on Wed, Mar 07, 2001 at 00:55:55 +0100 X-Mailer: Balsa 1.1.2 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On 03.07 Ying Chen wrote: > 2. We ran multi-threaded application using Linux pthread library on 2-way > SMP and UP intel platforms (with both 2.2 and 2.4 kernels). We see > significant increase in context switching when moving from UP to SMP, and > high CPU usage with no performance gain in turns of actual work being done > when moving to SMP, despite the fact the benchmark we are running is > CPU-bound. The kernel profiler indicates that the a lot of kernel CPU ticks > went to scheduling and signaling overheads. Has anyone seen something like > this before with pthread applications running on SMP platforms? Any > suggestions or pointers on this subject? > Too much contention ? How frequently do you create and destroy threads ? How much frequently do they access shared-writable-data ? How do you protect them ? It seems like your system spents more time creating and killing threads that doing real work. -- J.A. Magallon $> cd pub mailto:jamagallon@able.es $> more beer Linux werewolf 2.4.2-ac13 #3 SMP Wed Mar 7 00:09:17 CET 2001 i686