[Cbe-oss-dev] PS3 performance analysis - errors on loading cellperfctr module

[Uzi Shvadron]

"Julio M. Merino Vidal" <jmerino at ac.upc.edu> wrote on 12/12/2007 18:12:59:

> On 12/12/2007, at 16:42, Uzi Shvadron wrote:
>
> > On the PS3 (where I assume there is one user running one
> > application) there
> > might not be a need for the PDT kernel module. The module is used to
> > provide notifications on SPEs context switching. When the SPEs are
> > not over
> > committed (that is, the number of SPE threads is smaller or equal
> > to the
> > physical SPEs) there should be no context switching.
> > So, if your program and environment meet the above requirements you
> > should
> > be able to use PDT even if the kernel module is not installed and get
> > useful trace that can be analyzed by PDTR and VPA.
> >
>
> But consider that many PS3 are being used for research, and in those
> cases it is not uncommon to try to simulate busy boxes to see how the
> applications behave when they are not alone.  At least that's what
> I'm doing now.
>
> (And given that there is people porting all kinds of different
> applications to the Cell, with the primary focus on using them on the
> PS3, I can expect that there will be situations where the SPEs will
> be overcommitted.)

In this case a kernel that provides SPE context switches notifications to
the PDT kernel module should be made available to the PS3.

>
> Cheers,
>
> --
> Julio M. Merino Vidal <jmerino at ac.upc.edu>
>
>