Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 3 Jul 2001 14:24:32 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 3 Jul 2001 14:24:22 -0400 Received: from mysql.sashanet.com ([209.181.82.108]:11939 "EHLO mysql.sashanet.com") by vger.kernel.org with ESMTP id ; Tue, 3 Jul 2001 14:24:15 -0400 Content-Type: text/plain; charset=US-ASCII From: Sasha Pachev Organization: MySQL To: linux-kernel@vger.kernel.org Subject: Strange thread behaviour on 8-way x86 machine Date: Tue, 3 Jul 2001 12:25:12 -0600 X-Mailer: KMail [version 1.2] MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Message-Id: <0107031225120K.18621@mysql> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi, I have observed a rather strange behaviour doing a multi-threaded CPU benchmark on an 8-way machine running 2.4.2 SMP kernel. Even when the priority is reniced to the highest possible value, I am still unable to reach more than 50% CPU utilization. My benchmark just creates a bunch of threads with pthread_create(), and then runs a simple integer computation in each thread. On a dual with 2.4.3 kernel, and a 4-way with 2.4.2 kernel, I am able to reach full CPU utilization. At first glance, it appears to be like some overzealous fairness problem in the scheduler that is exhibited only when you have more than 4 CPUs. Before I start scrutinizing the source trying to understand the inner workings of the scheduler, I would like to get some feedback from people that know something about the subject. Any ideas/suggestions would be appreciated. -- MySQL Development Team For technical support contracts, visit https://order.mysql.com/ __ ___ ___ ____ __ / |/ /_ __/ __/ __ \/ / Sasha Pachev / /|_/ / // /\ \/ /_/ / /__ MySQL AB, http://www.mysql.com/ /_/ /_/\_, /___/\___\_\___/ Provo, Utah, USA <___/ - 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/