From owner-freebsd-arch@FreeBSD.ORG Sat Jan 19 14:21:21 2013 Return-Path: Delivered-To: arch@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by hub.freebsd.org (Postfix) with ESMTP id D260EA37 for ; Sat, 19 Jan 2013 14:21:21 +0000 (UTC) (envelope-from phk@phk.freebsd.dk) Received: from phk.freebsd.dk (phk.freebsd.dk [130.225.244.222]) by mx1.freebsd.org (Postfix) with ESMTP id 95D2EDEE for ; Sat, 19 Jan 2013 14:21:21 +0000 (UTC) Received: from critter.freebsd.dk (critter.freebsd.dk [192.168.61.3]) by phk.freebsd.dk (Postfix) with ESMTP id 83D618A51E; Sat, 19 Jan 2013 14:21:20 +0000 (UTC) Received: from critter.freebsd.dk (localhost [127.0.0.1]) by critter.freebsd.dk (8.14.5/8.14.5) with ESMTP id r0JELKBM001862; Sat, 19 Jan 2013 14:21:20 GMT (envelope-from phk@phk.freebsd.dk) To: Alfred Perlstein Subject: Re: RFC: enhanced watchdog. In-reply-to: <50FA3D36.4080709@mu.org> From: "Poul-Henning Kamp" References: <201301190604.r0J64RbW009298@svn.freebsd.org> <50FA3D36.4080709@mu.org> Date: Sat, 19 Jan 2013 14:21:20 +0000 Message-ID: <1861.1358605280@critter.freebsd.dk> Cc: "arch@freebsd.org" X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 19 Jan 2013 14:21:21 -0000 Content-Type: text/plain; charset=ISO-8859-1 -------- In message <50FA3D36.4080709@mu.org>, Alfred Perlstein writes: >We at iX are trying to enhance the watchdog and we think some of the >changes may benefit the community as a whole. The initial watchdog support was generalized from only two examples and therefore quite crude. I think your proposed improvements make good sense. I will generally warn you not to make things too complex though, it's important that the watchdog subsystem does not become a cause of failure on its own. Having a kernel thread which tries to get attention some delta-T before the hardware watchdog is supposed to kick in, also sounds like a good idea, but its information is going to be quite unreliable. One wish I have heard, was to be able to use multiple WD's separately, the current API sort of treats them as a redundant pool. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence.