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

Avi Kivity
2011-07-12T10:13:00Z

On 07/12/2011 01:03 PM, Joerg Roedel wrote:
> > 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.

I don't think it's workable. Having do_mmap() called in the task's
context can change how it works. And the task being able to kill/modify
the profile, and not able to use LWP for itself, is a show stopper IMO.

--
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