From owner-freebsd-hackers@FreeBSD.ORG Sun Jun 24 19:09:09 2012 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 D336E1065673 for ; Sun, 24 Jun 2012 19:09:09 +0000 (UTC) (envelope-from mjguzik@gmail.com) Received: from mail-ee0-f54.google.com (mail-ee0-f54.google.com [74.125.83.54]) by mx1.freebsd.org (Postfix) with ESMTP id 60EC28FC12 for ; Sun, 24 Jun 2012 19:09:09 +0000 (UTC) Received: by eeke49 with SMTP id e49so1293001eek.13 for ; Sun, 24 Jun 2012 12:09:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; bh=nmF2sJxS12GWcr2LCiq1dKbveNXgW88giOCY621gilo=; b=VyEPOnALgOjoj2/3Xcs9fGj0/uiICeWdFOQz/Jl5IZY7VGhDlfcLXbkI3PNBfdWHeS 3X70NXlkNK+OB5qrw/VmMZ3OQAiiVXYhmyj6mCSzpPpDlNO9HwpHdJaSpDsOd67ms2Ha hmcEIteRFqWlNk5wfFQHWNIZwzf5aXVj4Vk4rUPLUH355TOgVYzFyeyVtK0lcrCeBJjk Zo40Ld/0x9wUjn5CwJyA3V8h4PX6R7OFzbHzuqZ7mxvW6lP+9uA4S8dPxlW0lfZ7NWqd Xr5h9F9wci1Zm7ChVZUVnL/xnCYVlmCZ+fKiXiPLZXwVBTnzSmSHQoJMpqPZkOu9bQrO Fj6A== Received: by 10.14.28.202 with SMTP id g50mr1824065eea.167.1340564948366; Sun, 24 Jun 2012 12:09:08 -0700 (PDT) Received: from dft-labs.eu (n1x0n-1-pt.tunnel.tserv5.lon1.ipv6.he.net. [2001:470:1f08:1f7::2]) by mx.google.com with ESMTPS id u16sm131590636eeb.16.2012.06.24.12.09.07 (version=TLSv1/SSLv3 cipher=OTHER); Sun, 24 Jun 2012 12:09:07 -0700 (PDT) Date: Sun, 24 Jun 2012 21:08:53 +0200 From: Mateusz Guzik To: Wojciech Puchar Message-ID: <20120624190853.GB15899@dft-labs.eu> References: <20120623162415.303430@gmx.com> <20120624180526.GA15899@dft-labs.eu> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.20 (2009-06-14) Cc: freebsd-hackers@freebsd.org Subject: Re: reason for "magic" crashes. 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: Sun, 24 Jun 2012 19:09:09 -0000 On Sun, Jun 24, 2012 at 08:50:41PM +0200, Wojciech Puchar wrote: > >> > >> > >>There is nothing in cron that is done at sunday. > >> > >>i don't run "periodic" stuff in /etc/crontab > >> > > > >Compile the kernel with the following: > > > >makeoptions DEBUG="-O0 -g" > > > >options KDB # Enable kernel debugger support. > >options DDB # Support DDB. > >options GDB # Support remote GDB. > >options DEADLKRES # Enable the deadlock resolver > >options INVARIANTS # Enable calls of extra sanity checking > >options INVARIANT_SUPPORT # Extra sanity checks of internal structures, required by INVARIANTS > >options WITNESS # Enable checks to detect deadlocks and cycles > >options WITNESS_SKIPSPIN # Don't run witness on spinlocks for speed > >options DIAGNOSTIC > > > >After kernel panic ddb prompt will be waiting for you. Type in: > >dump > >reset > > > >Make sure you have swap that can handle crashdumps. > > already did this part and debug part, but not DDB. As you see - hang > not crashdump > > how much would it slow down whole thing? > > If less than 2 times it can be - CPU are rerely half loaded Are you asking about overhead of DDB or all debug options? I don't think that DDB support can be accounted for slowdown. As for the rest, it's hard to say. I guess it depends on your workload, also I never performed any benchmarks to compare this and I'm unaware of any. In other words, you have to test it yourself. -- Mateusz Guzik