Re: collect some information when qemu-kvm exit

[Jan Kiszka <jan.kiszka@siemens.com>]

On 2011-06-24 10:55, Jan Kiszka wrote:
> On 2011-06-24 10:24, lidong chen wrote:
>> 2011/6/23 Jan Kiszka <jan.kiszka@web.de>:
>>> 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

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