linux

powerpc: enable dynamic preemption Once the lazy preemption is supported, it would be desirable to change the preemption models at runtime. So add support for dynamic preemption using DYNAMIC_KEY. ::Tested lightly on Power10 LPAR Performance numbers indicate that, preempt=none(no dynamic) and preempt=none(dynamic) are close. cat /sys/kernel/debug/sched/preempt (none) voluntary full lazy perf stat -e probe:__cond_resched -a sleep 1 Performance counter stats for 'system wide': 1,253 probe:__cond_resched echo full > /sys/kernel/debug/sched/preempt cat /sys/kernel/debug/sched/preempt none voluntary (full) lazy perf stat -e probe:__cond_resched -a sleep 1 Performance counter stats for 'system wide': 0 probe:__cond_resched Signed-off-by: Shrikanth Hegde <sshegde@linux.ibm.com> Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com> Link: https://patch.msgid.link/20250210184334.567383-2-sshegde@linux.ibm.com 2025-02-11 00:13:34 +05:30