> -----Original Message-----
> From: Peter Zijlstra [mailto:[email protected]]
> Sent: Thursday, December 3, 2020 10:29 PM
> To: Valentin Schneider <[email protected]>
> Cc: Song Bao Hua (Barry Song) <[email protected]>;
> [email protected]; [email protected]; [email protected]; [email protected];
> [email protected]; Jonathan Cameron <[email protected]>;
> [email protected]; [email protected]; [email protected];
> [email protected]; [email protected]; [email protected];
> [email protected]; [email protected]; [email protected];
> [email protected]; [email protected]; Linuxarm
> <[email protected]>; xuwei (O) <[email protected]>; Zengtao (B)
> <[email protected]>
> Subject: Re: [RFC PATCH v2 2/2] scheduler: add scheduler level for clusters
>
> On Tue, Dec 01, 2020 at 04:04:04PM +0000, Valentin Schneider wrote:
> >
> > Gating this behind this new config only leveraged by arm64 doesn't make it
> > very generic. Note that powerpc also has this newish "CACHE" level which
> > seems to overlap in function with your "CLUSTER" one (both are arch
> > specific, though).
> >
> > I think what you are after here is an SD_SHARE_PKG_RESOURCES domain walk,
> > i.e. scan CPUs by increasing cache "distance". We already have it in some
> > form, as we scan SMT & LLC domains; AFAICT LLC always maps to MC, except
> > for said powerpc's CACHE thingie.
>
> There's some intel chips with a smaller L2, but I don't think we ever
> bothered.
>
> There's also the extended topology stuff from Intel: SMT, Core, Module,
> Tile, Die, of which we've only partially used Die I think.
>
> Whatever we do, it might make sense to not all use different names.
Yep. Valentin was actually recommending the same SD_SHARE_PKG_RESOURCES sd flags
by ignoring the actual names of the hardware.
But the question is where we should start, in case we have 3 domains under llc,
maybe it is not good to scan from the first level domain as it is gathering
too much.
>
> Also, I think Mel said he was cooking something for
> select_idle_balance().
>
> Also, I've previously posted patches that fold all the iterations into
> one, so it might make sense to revisit some of that if Mel also already
> didn.t
Would you point out the link of your previous patches?
Thanks
Barry
