Re: [Qemu-devel] [PATCH 0/5] Add some tracepoints for clarification of the cause of troubles

[Kazuya Saito]

(2013/03/22 20:13), Paolo Bonzini wrote:
> Il 22/03/2013 09:25, Kazuya Saito ha scritto:
>> This series adds tracepoints for helping us clarify the cause of
>> troubles. Virtualization on Linux is composed of some components such
>> as qemu, kvm, libvirt, and so on. So it is very important to clarify
>> firstly and swiftly the cause of troubles is on what component of
>> them. Although qemu has useful information of this because it stands
>> among kvm, libvirt and guest, it doesn't output the information by
>> trace or log system.
>> These patches add tracepoints which lead to reduce the time of the
>> clarification. We'd like to add the tracepoints as the first set
>> because, based on our experience, we've found out they must be useful
>> for an investigation in the future. Without those tracepoints,
>> we had a really hard time investigating a problem since the problem's
>> reproducibility was quite low and there was no clue in the dump of
>> qemu.
>>
>> Kazuya Saito (5):
>>   vl: add runstate_set tracepoint
>>   kvm-all: add kvm_ioctl, kvm_vm_ioctl, kvm_vcpu_ioctl tracepoints
>>   kvm-all: add kvm_run_exit tracepoint
>>   qdev: add qdev_{create,free} tracepoints
>>   qdev-monitor: add device_add tracepoint
> 
> I'm not sure 4-5 are that useful, but the first 3 patches are definitely
> good stuff.

Thanks. I'll modify the patch you pointed out about CPU number and
re-post it.
I'd like to add tracepoints to the virtual device creation/deletion
part.  I had an issue that when a Windows guest OS booted up, it didn't
have a virtual NIC device which it should have had.  It took us time to
figure out which the guest OS or the QEMU had the issue.  If I have
had the tracepoints in the virtual device creation/deletion should have
eased the situation much better.

Kazuya