From owner-freebsd-current@FreeBSD.ORG Fri Oct 7 15:16:50 2005 Return-Path: X-Original-To: freebsd-current@FreeBSD.org Delivered-To: freebsd-current@FreeBSD.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 8812B16A41F; Fri, 7 Oct 2005 15:16:50 +0000 (GMT) (envelope-from cswiger@mac.com) Received: from vms042pub.verizon.net (vms042pub.verizon.net [206.46.252.42]) by mx1.FreeBSD.org (Postfix) with ESMTP id 42CE143D45; Fri, 7 Oct 2005 15:16:50 +0000 (GMT) (envelope-from cswiger@mac.com) Received: from [192.168.1.3] ([68.161.71.31]) by vms042.mailsrvcs.net (Sun Java System Messaging Server 6.2 HotFix 0.04 (built Dec 24 2004)) with ESMTPA id <0INZ004TGX3WPHZ3@vms042.mailsrvcs.net>; Fri, 07 Oct 2005 10:16:44 -0500 (CDT) Date: Fri, 07 Oct 2005 11:16:46 -0400 From: Chuck Swiger In-reply-to: <20051007142107.GD14542@cell.sick.ru> To: Gleb Smirnoff Message-id: <4346915E.6040106@mac.com> Organization: The Courts of Chaos MIME-version: 1.0 Content-type: text/plain; charset=us-ascii; format=flowed Content-transfer-encoding: 7bit X-Accept-Language: en-us, en References: <00e401c5cb48$de24e190$6504010a@Jura> <20051007142107.GD14542@cell.sick.ru> User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.12) Gecko/20050915 Cc: freebsd-current@FreeBSD.org, "Yuriy N. Shkandybin" Subject: Re: [HEADSUP] big polling changes X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 07 Oct 2005 15:16:50 -0000 Gleb Smirnoff wrote: > On Fri, Oct 07, 2005 at 06:10:26PM +0400, Yuriy N. Shkandybin wrote: > Y> polling + kern.polling.idle_poll=1 > Y> CPU states: 0.2% user, 0.0% nice, 59.3% system, 21.3% interrupt, 19.2% > Y> idle > Y> but about +10 % perfomance thoughput > > This is normal and known for idle_poll. Is this because polling now fires the device interrupt every so often even while idle? If so, could this behavior obtain a threshold to limit the maximum number of interrupts being added when the device is idle? I've been seeing interupt storms back in 5.4, especially when a USB controller and a NIC share an IRQ. Another thing to consider might be to switch in and out of polling mode dynamicly, which would let you operate in interrupt-driven mode if the network is quiet or silent, but would go into polling mode once there is enough traffic to make doing so a benefit. Once you go into polling mode, stay there until the network becomes silent again. -- -Chuck