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

Frank Ch. Eigler
2010-03-16T16:08:22Z

Hi -

On Tue, Mar 16, 2010 at 04:52:21PM +0100, Ingo Molnar wrote:
> [...]
> > Perhaps the fact that kvm happens to deal with an interesting application
> > area (virtualization) is misleading here. As far as the host kernel or
> > other host userspace is concerned, qemu is just some random unprivileged
> > userspace program [...]

> You are quite mistaken: KVM isnt really a 'random unprivileged
> application' in this context, it is clearly an extension of
> system/kernel services.

I don't know what "extension of system/kernel services" means in this
context, beyond something running on the system/kernel, like every
other process. To clarify, to what extent do you consider your
classification similarly clear for a host is running

* multiple kvm instances run as unprivileged users
* non-kvm OS simulators such as vmware or xen or gdb
* kvm instances running something other than linux

> ( Which can be seen from the simple fact that what started the
> discussion was 'how do we get /proc/kallsyms from the
> guest'. I.e. an extension of the existing host-space /proc/kallsyms
> was desired. )

(Sorry, that smacks of circular reasoning.)

It may be a charming convenience function for perf users to give them
shortcuts for certain favoured configurations (kvm running freshest
linux), but that says more about perf than kvm.

- FChE