Re: [RFC] Unify KVM kernel-space and user-space code into a single project

Ingo Molnar
2010-03-22T15:55:37Z

* Anthony Liguori <anthony@codemonkey.ws> wrote:

> [...]
>
> I've been trying very hard to turn this into a productive thread attempting
> to capture your feedback and give clear suggestions about how you can solve
> achieve your desired functionality.

I'm glad that we are at this more productive stage. I'm still trying to
achieve the very same technological capabilities that i expressed in the first
few mails when i reviewed the 'perf kvm' patch that was submitted by Yanmin.

The crux of the problem is very simple. To quote my earlier mail:

|
| - The inconvenience of having to type:
| perf kvm --host --guest --guestkallsyms=/home/ymzhang/guest/kallsyms \
| --guestmodules=/home/ymzhang/guest/modules top
|
|
| is very obvious even with a single guest. Now multiply that by more guests ...
|

For example we want 'perf kvm top' to do something useful by default: it
should find the first guest running and it should report its profile.

The tool shouldnt have to guess about where the guests are, what their
namespaces is and how to talk to them. We also want easy symbolic access to
guest, for example:

perf kvm -g OpenSuse-2 record sleep 1

I.e.:

- Easy default reference to guest instances, and a way for tools to
reference them symbolically as well in the multi-guest case. Preferably
something trustable and kernel-provided - not some indirect information
like a PID file created by libvirt-manager or so.

- Guest-transparent VFS integration into the host, to recover symbols and
debug info in binaries, etc.

There were a few responses to that but none really addressed those problems -
they mostly tried to re-define the problem and suggested that i was wrong to
want such capabilities and suggested various inferior approaches instead. See
the thread for the details - i think i covered every technical suggestion that
was made.

So we are still at an impasse as far as i can see. If i overlooked some
suggestion that addresses these problems then please let me know ...

Thanks,

Ingo