x86/perf/intel/cstate: Make cstate hotplug handling actually work
The current implementation aside of being an incomprehensible mess is broken. # cat /sys/bus/event_source/devices/cstate_core/cpumask 0-17 That's on a quad socket machine with 72 physical cores! Qualitee stuff. So it's not a surprise that event migration in case of CPU hotplug does not work either. # perf stat -e cstate_core/c6-residency/ -C 1 sleep 60 & # echo 0 >/sys/devices/system/cpu/cpu1/online Tracing cstate_pmu_event_update gives me: [001] cstate_pmu_event_update <-event_sched_out After the fix it properly moves the event: [001] cstate_pmu_event_update <-event_sched_out [073] cstate_pmu_event_update <-__perf_event_read [073] cstate_pmu_event_update <-event_sched_out The migration of pkg events does not work either. Not that I'm surprised. I really could not be bothered to decode that loop mess and simply replaced it by querying the proper cpumasks which give us the answer in a comprehensible way. This also requires to direct the event to the current active reader CPU in cstate_pmu_event_init() otherwise the hotplug logic can't work. Signed-off-by: NThomas Gleixner <tglx@linutronix.de> [ Added event->cpu < 0 test to not explode] Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@suse.de> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Kan Liang <kan.liang@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Vince Weaver <vincent.weaver@maine.edu> Link: http://lkml.kernel.org/r/20160320185623.422519970@linutronix.deSigned-off-by: NIngo Molnar <mingo@kernel.org>
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