Commit 4e71de79 authored by Zhou Chengming's avatar Zhou Chengming Committed by Thomas Gleixner
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perf/x86/intel: Handle exclusive threadid correctly on CPU hotplug

The CPU hotplug function intel_pmu_cpu_starting() sets
cpu_hw_events.excl_thread_id unconditionally to 1 when the shared exclusive
counters data structure is already availabe for the sibling thread.

This works during the boot process because the first sibling gets threadid
0 assigned and the second sibling which shares the data structure gets 1.

But when the first thread of the core is offlined and onlined again it
shares the data structure with the second thread and gets exclusive thread
id 1 assigned as well.

Prevent this by checking the threadid of the already online thread.

[ tglx: Rewrote changelog ]
Signed-off-by: default avatarZhou Chengming <>
Cc: NuoHan Qiao <>

Signed-off-by: default avatarThomas Gleixner <>
---					---
 arch/x86/events/intel/core.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)
parent 49def185
......@@ -3176,13 +3176,16 @@ static void intel_pmu_cpu_starting(int cpu)
if (x86_pmu.flags & PMU_FL_EXCL_CNTRS) {
for_each_cpu(i, topology_sibling_cpumask(cpu)) {
struct cpu_hw_events *sibling;
struct intel_excl_cntrs *c;
c = per_cpu(cpu_hw_events, i).excl_cntrs;
sibling = &per_cpu(cpu_hw_events, i);
c = sibling->excl_cntrs;
if (c && c->core_id == core_id) {
cpuc->kfree_on_online[1] = cpuc->excl_cntrs;
cpuc->excl_cntrs = c;
cpuc->excl_thread_id = 1;
if (!sibling->excl_thread_id)
cpuc->excl_thread_id = 1;
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