Re: [PATCH] sched/debug: Introduce per-CPU debugfs files

[Peter Zijlstra]

On Mon, Jul 27, 2026 at 10:03:09PM -0400, Aaron Tomlin wrote:
> Currently, accessing scheduler debugging details for a specific CPU
> requires reading /sys/kernel/debug/sched/debug, which outputs
> information for all online CPUs. This results in redundant output and
> parsing overhead on large SMP systems when targeting an individual CPU.
> 
> Add support for per-CPU debug files under:
> /sys/kernel/debug/sched/cpu/cpu<N>/debug. Reading
> /sys/kernel/debug/sched/cpu/cpu<N>/debug calls print_cpu() specifically
> for CPU <N>, exposing CPU-specific runqueue details on demand.

You're failing to explain why though. In what situation does the
overhead from sched/debug matter one whit? If you're dumping this at
frequencies high enough for this to matter, you're doing something
terribly wrong.