[PATCH v2 0/4] powerpc/topology: Introduce llc_override kernel parameter

From: Shrikanth Hegde

Date: Fri Oct 23 2026 - 09:17:55 EST


Provide an option for users to enable cache aware scheduling on powerpc
via a command line parameter.

More details of the problem and context is in cover-letter of v1.
v1: https://lore.kernel.org/all/20261012102037.2477378-1-sshegde@xxxxxxxxxxxxx/

v1->v2:
- Move to kernel parameters from debugfs. This helps to keep
llc_id consistent which doesn't change across sched domain
rebuilds. (Tim Chen)
- Update arch_llc_mask to reflect the override (Tim Chen)
- Limit only to mc, pkg (Srikar Dronamraju)

Notes:

- A selftest for the functional validation of cache aware scheduling
is a good idea as we discussed in v1. It is a significant change on
its own and likely takes time. I am thinking it might be good idea to
revisit selftests for scheduler in general. (We have very few).
Maybe worth a discussion in coming OSPM.

- I am on parental leave. This version is pretty much what I had last week
and I haven't gotten any chance to update since. just sending it out.
Sorry if I have missed to address any comments.
Please expect delays in my response.

Shrikanth Hegde (4):
powerpc/topology: Introduce llc_override kernel parameter
powerpc/topology: Update mc/pkg flags based on llc_override
powerpc/topology: update arch_llc_mask based llc_override
Documentation/powerpc: Add details about llc_override

.../admin-guide/kernel-parameters.txt | 15 ++++
arch/powerpc/include/asm/topology.h | 8 +--
arch/powerpc/kernel/smp.c | 69 +++++++++++++++++--
3 files changed, 81 insertions(+), 11 deletions(-)

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2.52.0