Re: [PATCH 1/3] perf: add context field to perf_event

Joerg Roedel
2011-07-12T10:03:56Z

On Tue, Jul 12, 2011 at 12:55:25PM +0300, Avi Kivity wrote:

> Have a helper kernel thread do it for you. Or extend use_mm() to return
> the old mm (without dropping its refcount) and add a way to restore it.

Making use_mm usable for regular tasks too sounds like a good idea.
Thanks.

> Regarding LWP - I thought the intent was self-profiling by the process
> for jits and the like? If you also use it for perf, won't it be
> unusable for that? Also, can't the process interfere, from userspace,
> by executing the unprivileged LWP instructions?

Ingo made perf-integration a merge-requirement for LWP. It is not really
well-suited for being integrated into perf because the design goal was
easy and efficient self-profiling of tasks (like you stated). So
integrating it into perf causes some pain. But lets see how it works
out.

Joerg