Re: [PATCH] powerpc/smp: Dynamically build powerpc topology

[Peter Zijlstra]

On Wed, Aug 30, 2023 at 05:56:14PM +0530, Srikar Dronamraju wrote:
> Currently there are four powerpc specific sched topologies.  These are
> all statically defined.  However not all these topologies are used by
> all powerpc systems.
> 
> To avoid unnecessary degenerations by the scheduler , masks and flags
> are compared. However if the sched topologies are build dynamically then
> the code is simpler and there are greater chances of avoiding
> degenerations.
> 
> Even x86 builds its sched topologies dynamically and new changes are
> very similar to the way x86 is building its topologies.

You're not stating it explicitly, but you're doing this as a performance
optimization, right? The x86 thing didn't particularly care about
avoiding degenerate topologies -- it's just that the fixed tables method
grew unwieldy due to combinatorics.

And how does this patch relate to the other series touching this?

  powerpc/smp: Shared processor sched optimizations