From owner-freebsd-hackers@FreeBSD.ORG Sat Jan 31 14:33:41 2004 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 32ABC16A4CE for ; Sat, 31 Jan 2004 14:33:41 -0800 (PST) Received: from server.lab.cyberlifelabs.com (adsl-64-142-24-131.sonic.net [64.142.24.131]) by mx1.FreeBSD.org (Postfix) with ESMTP id 2444543D2F for ; Sat, 31 Jan 2004 14:33:40 -0800 (PST) (envelope-from milo@cyberlifelabs.com) Received: from [192.168.1.3] (beastie.lab.cyberlifelabs.com [192.168.1.3]) i0VMXdvn067297 for ; Sat, 31 Jan 2004 14:33:39 -0800 (PST) (envelope-from milo@cyberlifelabs.com) From: Milo Hyson To: freebsd-hackers@freebsd.org Content-Type: text/plain Message-Id: <1075588419.43166.6.camel@beastie.lab.cyberlifelabs.com> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.5 Date: Sat, 31 Jan 2004 14:33:39 -0800 Content-Transfer-Encoding: 7bit Subject: Weird context-switching performance X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 31 Jan 2004 22:33:41 -0000 We've got these two very similar machines that are exhibiting drastically different context-switching performance. The slower of the two is actually task-switching at four times the rate of the other. We've gone through several benchmarks and are at a complete loss to explain it. We've set up a page documenting our efforts: http://www.cyberlifelabs.com/cs-benchmark/ I would appreciate it if someone could offer some insight into what affects context-switching. Is there some obscure kernel variable that we've overlooked? Or is it just one of those unexplainable feng-shui situations? Thanks in advance. -- Milo Hyson Chief "Mad" Scientist CyberLife Labs, LLC