On Thu, Jan 26, 2023 at 08:55:27PM -0500, Waiman Long wrote:
The user_cpus_ptr field was originally added by commit b90ca8badbd1Dude, how can you still call this a slight performance regression after
("sched: Introduce task_struct::user_cpus_ptr to track requested
affinity"). It was used only by arm64 arch due to possible asymmetric
CPU setup.
Since commit 8f9ea86fdf99 ("sched: Always preserve the user requested
cpumask"), task_struct::user_cpus_ptr is repurposed to store user
requested cpu affinity specified in the sched_setaffinity().
This results in a slight performance regression on an arm64
system when booted with "allow_mismatched_32bit_el0"
Will told you time and time again that's not the problem.
It clearly is a behavioural problem.