[Mesa-dev] [PATCH 0/8] Gallium & RadeonSI optimization for Ryzen CPUs

[Marek Olšák]

On Fri, Sep 7, 2018, 4:34 AM Michel Dänzer <michel at daenzer.net> wrote:

> On 2018-09-06 10:56 p.m., Axel Davy wrote:
> > Yeah by pinning to cores, I meant to group of cores.
> >
> > I think a reasonable policy would be for the kernel to put all threads
> > of a given process on the same L3
> > as long as the number of threads is lower than the L3 group size.
> > When there is more threads I guess it'd need heuristics to pick which
> > threads to put together.
>
> Maybe what's needed is a way for userspace to tell the kernel which
> threads need to be close to each other in CPU topology.
>
>
> > I fear if we begin to do the work manually, there won't be interest to
> > do that in the kernel,
> > and thus all applications will need to include such core pinning code to
> > have good performance when
> > multithreaded.
>
> I'm also a bit worried that this solution could result in multiple
> processes contending for the same set of CPU cores, while other cores
> might be underused, which could result in worse overall system performance.
>

Any suggestion how to choose the ccx such that processes end up on a
different one?

I don't think the performance can be worse than it is right now.

Marek


>
> --
> Earthling Michel Dänzer               |               http://www.amd.com
> Libre software enthusiast             |             Mesa and X developer
>
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