From owner-freebsd-stable@FreeBSD.ORG Thu Mar 15 09:02:34 2007 Return-Path: X-Original-To: freebsd-stable@freebsd.org Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 0955516A403 for ; Thu, 15 Mar 2007 09:02:34 +0000 (UTC) (envelope-from bms@FreeBSD.org) Received: from out5.smtp.messagingengine.com (out5.smtp.messagingengine.com [66.111.4.29]) by mx1.freebsd.org (Postfix) with ESMTP id D4B3513C457 for ; Thu, 15 Mar 2007 09:02:33 +0000 (UTC) (envelope-from bms@FreeBSD.org) Received: from out1.internal (unknown [10.202.2.149]) by out1.messagingengine.com (Postfix) with ESMTP id 52D821F7E17; Thu, 15 Mar 2007 05:02:33 -0400 (EDT) Received: from heartbeat2.messagingengine.com ([10.202.2.161]) by out1.internal (MEProxy); Thu, 15 Mar 2007 05:02:33 -0400 X-Sasl-enc: cYtu2HTFFwJ2GiTmXzqFTpIKFPuCIVRfjntRtbhYpFWM 1173949353 Received: from [192.168.123.18] (82-35-112-254.cable.ubr07.dals.blueyonder.co.uk [82.35.112.254]) by mail.messagingengine.com (Postfix) with ESMTP id 263D4172C8; Thu, 15 Mar 2007 05:02:32 -0400 (EDT) Message-ID: <45F90BA6.7090102@FreeBSD.org> Date: Thu, 15 Mar 2007 09:02:30 +0000 From: "Bruce M. Simpson" User-Agent: Thunderbird 1.5.0.9 (X11/20070125) MIME-Version: 1.0 To: emilec@clarotech.co.za References: <000d01c766cd$3f6aef50$7efaa8c0@clarotech.co.za> In-Reply-To: <000d01c766cd$3f6aef50$7efaa8c0@clarotech.co.za> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: freebsd-stable@freebsd.org Subject: Re: Openvpn tap uses 99% cpu time X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 15 Mar 2007 09:02:34 -0000 Emile Coetzee wrote: > I have done some more investigation. Rolling back to RELENG_6_2 solves the > problem. I have now had this problem on 3 boxes in 2 days and have been able > to reproduce it on a 4th in our lab. > > Starting openvpn with full debug it stops just before the point where the > TAP devices gets initiated. And then the output from top shows openvpn on > 99% cpu time (well almost). > The recent changes to tap(4) were tested with openvpn and ppp before committing, and this is an isolated report at the moment. Other users on the list have suggested that the problem you are reporting does not affect FreeBSD alone. Please consider doing the following: 1. Use ktrace(8) to extract a kdump of openvpn as it runs into this problem, so that you may determine exactly which syscalls are invoked when you see this problem, and post it on this list. Consider using the ktrace pid mode to attach to openvpn as it blocks, as opposed to running openvpn under ktrace as a child process. 2. Implementing the usleep() fix as discussed by luigi, as the information in point 1 will give clues as to where the code is spinning. Regards, BMS