From owner-freebsd-hackers@FreeBSD.ORG Thu Apr 2 11:28:50 2009 Return-Path: Delivered-To: freebsd-hackers@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id C85F71065670 for ; Thu, 2 Apr 2009 11:28:50 +0000 (UTC) (envelope-from avg@icyb.net.ua) Received: from citadel.icyb.net.ua (citadel.icyb.net.ua [212.40.38.140]) by mx1.freebsd.org (Postfix) with ESMTP id 025C58FC13 for ; Thu, 2 Apr 2009 11:28:49 +0000 (UTC) (envelope-from avg@icyb.net.ua) Received: from odyssey.starpoint.kiev.ua (alpha-e.starpoint.kiev.ua [212.40.38.101]) by citadel.icyb.net.ua (8.8.8p3/ICyb-2.3exp) with ESMTP id OAA11518 for ; Thu, 02 Apr 2009 14:28:48 +0300 (EEST) (envelope-from avg@icyb.net.ua) Message-ID: <49D4A16F.6020906@icyb.net.ua> Date: Thu, 02 Apr 2009 14:28:47 +0300 From: Andriy Gapon User-Agent: Thunderbird 2.0.0.21 (X11/20090323) MIME-Version: 1.0 To: freebsd-hackers@FreeBSD.org X-Enigmail-Version: 0.95.7 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: Subject: watchdog: hw+sw? 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: Thu, 02 Apr 2009 11:28:51 -0000 I have some vague thoughts on using SW_WATCHDOG and a hardware watchdog together. I think this could be useful but I am not sure how to implement this. The idea is this: timeout for SW_WATCHDOG is smaller than timeout for hw wd; when some freeze happens sw wd logic kicks in first, stops hw wd and produces either panic or ddb prompt; if the freeze is so severe that sw wd can't run (e.g. hardware is messed up badly) then hw wd performs its duty. I am mostly interested in having this in unattended mode where kernel dump could be useful for later analysis but the system should recover in reasonable time. Suggestions, opinions? Thank you! -- Andriy Gapon