From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kiszka Subject: Re: collect some information when qemu-kvm exit Date: Fri, 24 Jun 2011 10:58:31 +0200 Message-ID: <4E0451B7.5000608@siemens.com> References: <4E0311BB.2000206@web.de> <4E035303.9070709@web.de> <4E0450F5.80809@siemens.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org To: lidong chen Return-path: Received: from thoth.sbs.de ([192.35.17.2]:18382 "EHLO thoth.sbs.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752044Ab1FXI6e (ORCPT ); Fri, 24 Jun 2011 04:58:34 -0400 In-Reply-To: <4E0450F5.80809@siemens.com> Sender: kvm-owner@vger.kernel.org List-ID: On 2011-06-24 10:55, Jan Kiszka wrote: > On 2011-06-24 10:24, lidong chen wrote: >> 2011/6/23 Jan Kiszka : >>> On 2011-06-23 15:56, lidong chen wrote: >>>>>> is it safe to register another signal handler? >>>>>> if somebody know the reason, please tell me. >>>>>> >>>>>> and is it worth to do this? >>>>> >>>> because the core dump file is too big, and the time of core dump is too long. >>>> I do a test, for a guest which have 9.7G memory, the coredump file is >>>> 9.7G, and the time of core dump is 1 minute. >>>> >>>> for the compute node in my system, there are a lot of cpu and memory >>>> resource, but no disk. >>>> >>>> >>>> total 4.5G >>>> -rw------- 1 root root 9.7G Jun 23 21:31 core-qemu-kvm-24090-1308835893 >>>> -rw------- 1 root root 3.9G Jun 23 21:34 core-qemu-kvm-24098-1308835996 >>> >>> ulimit -c allows you to restrict the core file size so that it fits on >>> your ram disk. That will at least collect enough information to do a >>> proper post-mortem backtrace in gdb, including register states. It also >>> allows to inspect variables on the stacks and the heap. No need to add a >>> singe line or code to qemu for this. >>> >> >> if i use 'ulimit -c 6000' to restrict the core file, the backtrace >> can't work correctly. > > I've granted a few hundred megs, and it worked for me. > >> >> 26:/corefile # gdb /usr/bin/qemu-kvm core-qemu-kvm-9979-1308888098 >> GNU gdb (GDB) SUSE (7.0-0.4.16) And I've gdb 7.2.50.20101006-cvs here. Maybe that also contributes to a working setup. Jan -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux