Re: [PATCH] Enhance perf to collect KVM guest os statistics from host side

Anthony Liguori
2010-03-16T23:07:11Z

On 03/16/2010 12:39 PM, Ingo Molnar wrote:
>> If we look at the use-case, it's going to be something like, a user is
>> creating virtual machines and wants to get performance information about
>> them.
>>
>> Having to run a separate tool like perf is not going to be what they would
>> expect they had to do. Instead, they would either use their existing GUI
>> tool (like virt-manager) or they would use their management interface
>> (either QMP or libvirt).
>>
>> The complexity of interaction is due to the fact that perf shouldn't be a
>> stand alone tool. It should be a library or something with a programmatic
>> interface that another tool can make use of.
>>
> But ... a GUI interface/integration is of course possible too, and it's being
> worked on.
>
> perf is mainly a kernel developer tool, and kernel developers generally dont
> use GUIs to do their stuff: which is the (sole) reason why its first ~850
> commits of tools/perf/ were done without a GUI. We go where our developers
> are.
>
> In any case it's not an excuse to have no proper command-line tooling. In fact
> if you cannot get simpler, more atomic command-line tooling right then you'll
> probably doubly suck at doing a GUI as well.
>

It's about who owns the user interface.

If qemu owns the user interface, than we can satisfy this in a very
simple way by adding a perf monitor command. If we have to support
third party tools, then it significantly complicates things.

Regards,

Anthony Liguori

> Ingo
>