From owner-freebsd-current@FreeBSD.ORG Wed Mar 11 20:55:33 2009 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 0A1061065674 for ; Wed, 11 Mar 2009 20:55:33 +0000 (UTC) (envelope-from kalinoj1@iem.pw.edu.pl) Received: from volt.iem.pw.edu.pl (volt.iem.pw.edu.pl [194.29.146.3]) by mx1.freebsd.org (Postfix) with ESMTP id 552448FC13 for ; Wed, 11 Mar 2009 20:55:30 +0000 (UTC) (envelope-from kalinoj1@iem.pw.edu.pl) Received: by volt.iem.pw.edu.pl (Postfix, from userid 80) id 4C1B4A66734; Wed, 11 Mar 2009 21:39:17 +0100 (CET) To: MIME-Version: 1.0 Date: Wed, 11 Mar 2009 21:39:17 +0100 From: =?UTF-8?Q?J=C4=99drzej_Kalinowski?= Message-ID: <3cd67c0d967b2464a4b40bd85582bf88@iem.pw.edu.pl> X-Sender: kalinoj1@iem.pw.edu.pl User-Agent: RoundCube Webmail/0.2-beta Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset="UTF-8" X-Mailman-Approved-At: Wed, 11 Mar 2009 21:12:10 +0000 Subject: Timer issues when running CURRENT inside qemu 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: Wed, 11 Mar 2009 20:55:33 -0000 Hello, I'm using the latest qemu release (0.10.0) to simulate network boot of the FreeBSD diskless station. Recent qemu supports HPET timer emulation (and does it by default). I've found something that could be interesting to -CURRENT developers... When I boot a 8.0-CURRENT kernel I've got console and dmesg full of such information: calcru: runtime went backwards from 981954 usec to 282875 usec for pid 14 (sh) calcru: runtime went backwards from 11248014703054744 usec to 23653848 usec forpid 14 (sh) calcru: runtime went backwards from 1298297 usec to 909205 usec for pid 11 (intr) calcru: runtime went backwards from 11248014678717988 usec to 119242 usec for pid 60 (ps) calcru: runtime went backwards from 11248014678921829 usec to 2516605 usec for pid 60 (ps) calcru: runtime went backwards from 7014844 usec to 6270851 usec for pid 0 (kernel) calcru: runtime went backwards from 11248014678723366 usec to 31380 usec for pid 15 (nfsiod 0) calcru: runtime went backwards from 22496029384944496 usec to 37978168 usec for pid 14 (sh) I also get events like this (which makes my console session die, or for example ssh to fail): login: Mar 11 21:15:12 qemu kernel: pid 831 (getty), uid 0, was killed: exceeded maximum CPU limit Sysctl shows these timers. qemu% sysctl kern.timecounter.choice kern.timecounter.choice: TSC(800) HPET(900) ACPI-safe(850) i8254(0) dummy(-1000000) I tried to switch between them, but any of them helps. I don't remember experiencing such things when running 7.x or 6.x series so maybe it's a new issue. It happens regardless of kqemu usage. Of course if you find this interesting and need some more info from dmesg or sth - I'm at your service :) -- Regards, Jedrzej Kalinowski