From owner-freebsd-alpha Tue May 9 13: 0:29 2000 Delivered-To: freebsd-alpha@freebsd.org Received: from finch-post-12.mail.demon.net (finch-post-12.mail.demon.net [194.217.242.41]) by hub.freebsd.org (Postfix) with ESMTP id BC57F37C20A for ; Tue, 9 May 2000 12:46:15 -0700 (PDT) (envelope-from dfr@nlsystems.com) Received: from nlsys.demon.co.uk ([158.152.125.33] helo=herring.nlsystems.com) by finch-post-12.mail.demon.net with esmtp (Exim 2.12 #1) id 12pFxJ-0003F3-0C; Tue, 9 May 2000 19:46:10 +0000 Received: from salmon.nlsystems.com (salmon.nlsystems.com [10.0.0.3]) by herring.nlsystems.com (8.9.3/8.8.8) with ESMTP id UAA48266; Tue, 9 May 2000 20:49:16 +0100 (BST) (envelope-from dfr@nlsystems.com) Date: Tue, 9 May 2000 20:50:46 +0100 (BST) From: Doug Rabson To: Valentin Nechayev Cc: freebsd-alpha@freebsd.org Subject: Re: multi-session dmesg In-Reply-To: <20000509160051.B83860@lucky.net> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-alpha@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org On Tue, 9 May 2000, Valentin Nechayev wrote: > At our current system (4.0-20000502-STABLE), dmesg buffer is not cleared > during system boot and contains previous data. This looks as following: > > === cut part of /var/run/dmesg === > dc0: TX underrun -- increasing TX threshold > dc0: TX underrun -- increasing TX threshold > dc0: TX underrun -- increasing TX threshold > Waiting (max 60 seconds) for system process `bufdaemon' to stop...stopped > Waiting (max 60 seconds) for system process `syncer' to stop...stopped > > syncing disks... 31 30 27 20 9 > done > Uptime: 26m9s > Rebooting... > Copyright (c) 1992-2000 The FreeBSD Project. > Copyright (c) 1982, 1986, 1989, 1991, 1993 > The Regents of the University of California. All rights reserved. > FreeBSD 4.0-STABLE #0: Tue May 2 23:54:37 EEST 2000 > root@aleph.carrier.kiev.ua:/var/src/sys/compile/ALEPH > EB164 > Digital AlphaPC 164SX 533 MHz, 531MHz > === end cut === > > Is it bug or feature? > I strongly want it to be feature because this buffer may contain panic report > and previous important messages in panic case. This is a feature. The message buffer is always in the same place in memory and if its contents survive the reboot (there are magic numbers which are checked), then the kernel keeps the contents. Its extremely useful when hacking on kernels. -- Doug Rabson Mail: dfr@nlsystems.com Nonlinear Systems Ltd. Phone: +44 20 8442 9037 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-alpha" in the body of the message