Re: [patch 02/24] perfmon: base code

[Thomas Gleixner <tglx@linutronix.de>]

Stephane,

On Thu, 27 Nov 2008, stephane eranian wrote:

> >> session is independent of each other. You can therefore measure different
> >> things on different CPUs. Reservation is thus done independently for each
> >> CPU, therefore we need a cpu bitmask  to track allocation.
> >
> > Ok. Question: if you do a one CPU wide session with perfom, can you
> > still do thread monitoring on the same CPU ?
> >
> No. They are currently mutually exclusive.
> 
> > If no, what prevents that a monitored thread is migrated to such a CPU ?
> >
> Nothing. AND you don't want to change affinity because you are monitoring.
> So the current restriction is that cpu-wide and per-thread are
> mutually exclusive.

And how is this achieved ? Currently there seems nothing which
prevents a per-thread vs. cpu-wide monitoring.

Thanks,

	tglx