From owner-freebsd-hackers@FreeBSD.ORG Tue Jul 18 19:00:36 2006 Return-Path: X-Original-To: freebsd-hackers@freebsd.org 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 BAD0616A4DF for ; Tue, 18 Jul 2006 19:00:36 +0000 (UTC) (envelope-from jhb@freebsd.org) Received: from server.baldwin.cx (66-23-211-162.clients.speedfactory.net [66.23.211.162]) by mx1.FreeBSD.org (Postfix) with ESMTP id 078E543D4C for ; Tue, 18 Jul 2006 19:00:35 +0000 (GMT) (envelope-from jhb@freebsd.org) Received: from localhost.corp.yahoo.com (john@localhost [127.0.0.1]) (authenticated bits=0) by server.baldwin.cx (8.13.4/8.13.4) with ESMTP id k6IJ0TOm055606; Tue, 18 Jul 2006 15:00:30 -0400 (EDT) (envelope-from jhb@freebsd.org) From: John Baldwin To: freebsd-hackers@freebsd.org Date: Tue, 18 Jul 2006 14:41:26 -0400 User-Agent: KMail/1.9.1 References: <200607181317.33416.gmccaughan@synaptics-uk.com> <44BD044A.4090509@rojer.pp.ru> <200607181804.44813.gmccaughan@synaptics-uk.com> In-Reply-To: <200607181804.44813.gmccaughan@synaptics-uk.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-6" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200607181441.26875.jhb@freebsd.org> X-Greylist: Sender succeeded SMTP AUTH authentication, not delayed by milter-greylist-2.0.2 (server.baldwin.cx [127.0.0.1]); Tue, 18 Jul 2006 15:00:33 -0400 (EDT) X-Virus-Scanned: ClamAV 0.87.1/1604/Tue Jul 18 11:41:03 2006 on server.baldwin.cx X-Virus-Status: Clean X-Spam-Status: No, score=-4.4 required=4.2 tests=ALL_TRUSTED,BAYES_00 autolearn=ham version=3.1.0 X-Spam-Checker-Version: SpamAssassin 3.1.0 (2005-09-13) on server.baldwin.cx Cc: Deomid Ryabkov , Gareth McCaughan Subject: Re: "swiN: clock sio" process taking 75% CPU X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 18 Jul 2006 19:00:36 -0000 On Tuesday 18 July 2006 13:04, Gareth McCaughan wrote: > On Tuesday 2006-07-18 16:54, Deomid Ryabkov wrote: > > Gareth McCaughan wrote: > > > > > About 6 minutes after booting (on three occasions, but I > > > don't guarantee this doesn't vary), a process (well, a > > > kernel interrupt thread, I guess) that appears in the > > > output of "ps" as "[swi4: clock sio]" begins to use > > > about 3/4 of the machine's CPU. > > > > I recall seeing similar behavior on a Sun V20z, running 5.x at the time. > > I have definitely seen a lot of interrupts and CPU usage on the sio interrupt > > corresponding to serial console. Needless to say there was no activity > > on the console itself. > > I think turning off serial console solved that for me. > > Do you mean commenting out the entries in /etc/ttys related to > serial TTYs, or something else? (I've tried the former, and it > didn't help.) > > In the spirit of grotesque voodoo chicken-waving, I also tried > taking the "sio" device out of my kernel entirely. The problem > remains unaltered. In that case, something is scheduling a lot of timeouts (via callout_reset() or timeout()) or you have timeout handlers that are taking a very long time to run. There aren't any easy ways to debug this. :-P You can try turning on the DIGANOSTIC check in kern_timeout.c to catch long-running timeouts, and you can try adding some KTR traces to softclock() to see which timeout functions are running and try to do some analysis on that. -- John Baldwin