Re: [PATCH RFC] sched_ext: Choose prev_cpu if idle and cache affine without WF_SYNC

[Peter Zijlstra]

On Mon, Mar 17, 2025 at 06:30:57PM +0100, Andrea Righi wrote:

> I guess the question is: what is more expensive in general on task wakeup?
> 1) a cross-node migration or 2) running on a partially busy SMT core?

That totally depends on both the workload and the actual machine :/

If you have 'fast' numa and not a very big footprint, the numa
migrations aren't too bad. OTOH if you have sucky numa or your memory
footprint is significant, then running on the wrong node is super
painful.