Re: [PATCH 0/4] powerpc/topology: Introduce llc_override debugfs

On 10/13/2026 5:15 AM, Tim Chen wrote:

On Mon, 2026-10-12 at 15:50 +0530, Shrikanth Hegde wrote:

[ ... ]

quoted

Tim, Chenyu, Peter,
Are there any selftest or patches which is used for
functional validation of cache aware scheduling?

We haven't created one. We validate mostly with workloads such as
hackbench, schbench and yogini (which can vary the number of threads
over time and track CPU assignment). I agree they are not ideal for
functional checks of the load balance path.

quoted

per-LLC occupancy in /proc/{PID}/schedstat may not tell the full
story when there are multiple processes and multiple LLC's.

Atleast for functional verification, we might need one if there is
not one already. The reason being,
- At present, we may need a custom workload. hackbench/schbench are
   wakeup intensive and typically bail out even before load balance.
- stress-ng is per process. So doesn't get cache aware scheduling.
- A selftest could spwan specific number of threads till llc size etc
   and ensure packing happens till core_count(llc_size) by default.
   This could also be used for tunable verfifications.
- Provide an ability to observe how much of the workload was contained
   within the LLC due to cache aware scheduling or number of load
   balances stopped due to preferred llc.

A selftest would be great and much welcomed.

Yes, that would be very useful. For functional testing, previously we
asked AI to generate a trial test script to launch a random number of
while(1) tests and watch their occupancy on each LLC.

thanks,
Chenyu