From owner-freebsd-arch@FreeBSD.ORG Tue Mar 22 20:19:24 2011 Return-Path: Delivered-To: freebsd-arch@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id E285D106564A for ; Tue, 22 Mar 2011 20:19:24 +0000 (UTC) (envelope-from mj@feral.com) Received: from ns1.feral.com (ns1.feral.com [192.67.166.1]) by mx1.freebsd.org (Postfix) with ESMTP id B352A8FC12 for ; Tue, 22 Mar 2011 20:19:24 +0000 (UTC) Received: from ghanima.in1.lcl (ghanima.in1.lcl [172.16.1.87]) by ns1.feral.com (8.14.4/8.14.3) with ESMTP id p2MJsnPD012168; Tue, 22 Mar 2011 11:54:49 -0800 (PST) (envelope-from mj@feral.com) Message-ID: <4D88FE89.1060900@feral.com> Date: Tue, 22 Mar 2011 12:54:49 -0700 From: Matthew Jacob User-Agent: Thunderbird 2.0.0.24 (X11/20101213) MIME-Version: 1.0 To: John Baldwin References: <201103221551.14289.jhb@freebsd.org> In-Reply-To: <201103221551.14289.jhb@freebsd.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.6 (ns1.feral.com [192.67.166.1]); Tue, 22 Mar 2011 11:54:49 -0800 (PST) Cc: "Bjoern A. Zeeb" , freebsd-arch@freebsd.org Subject: Re: kernel memory checks on boot vs. boot time X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 22 Mar 2011 20:19:25 -0000 John Baldwin wrote: > > Do other platforms bother with these sorts of memory tests? If not I'd vote > to just drop it. I think this mattered more when you didn't have things like > SMAP (so you had to guess at where memory ended sometimes). Also, modern > server class x86 machines generally support ECC RAM which will trigger a > machine check if there is a problem. I doubt that the early checks are > catching anything even for the non-ECC case. > > If nothing else, I would definitely drop this from amd64 (all those systems > have SMAP and machine check support, etc.). > > Memory checks are definitely still useful. Loading the linux mem tester has helped find lots of problems, even on so-called modern machines. I'd voter for leaving this as an option.