Re: [Qemu-discuss] [Qemu-devel] Libvirt add ftrace option

[Gadre Nayan]

Hi,

I have setup the merging of traces from Guest QEMU and Host using the
TSC_OFFSET. So I would like to work with ftrace backend of QEMU. So
how can I add this option in libvirt tools to enable ftrace backends
with my custom qemu source built using --enable-trace-backends=ftrace.

I would have to make changes to virt-install python script in the
virt-manager tools for starters ( to parse the trace options :). Where
else ?

Thanks



On Tue, Aug 16, 2016 at 7:48 PM, Daniel P. Berrange <address@hidden> wrote:
> On Tue, Aug 16, 2016 at 07:33:30PM +0530, Gadre Nayan wrote:
>> Hi,
>>
>> I am able to get traces from Guest kernel + QEMU + Host kernel using the
>> qemu -trace evetns=/tmp/events option
>>
>> My complete command line is:
>> /home/gnayan/QEMU-devel/qemu-ubuntu/qemu/x86_64-softmmu/qemu-system-x86_64
>> -trace events=/home/gnayan/qemu_events -drive
>> file=/home/gnayan/CUSTOM_QEMU_SYSTEM/UBUNTU/ubuntu.img,if=virtio,format=raw
>> -drive 
>> file=/home/gnayan/CUSTOM_QEMU_SYSTEM/UBUNTU/u1.img,if=virtio,format=raw
>> -m 1G -net nic,model=virtio -net user -redir tcp:2222::22 -redir
>> udp:5050::5050 -enable-kvm
>>
>> How can I get the same using libvirt based tools:
>>
>> I create the domain using:
>>
>> virt-install -n vm1 -r 1024 --disk
>> path=/home/gnayan/CUSTOM_QEMU_SYSTEM/UBUNTU/ubuntu.img,bus=virtio
>> --network network=default,model=virtio
>>
>> Is the trace option available ?
>
> With libvirt you should use the dtrace/systemtap backend instead as that's
> far more flexible, not requiring changes to the QEMU configuration every
> time you want to change what events are output.
>
> Regards,
> Daniel
> --
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