Messages in this thread Patch in this message | | | From | kan.liang@linux ... | Subject | [PATCH V4 5/5] perf/x86: Fix: disable userspace RDPMC usage for large PEBS | Date | Mon, 12 Feb 2018 14:20:35 -0800 |
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From: Kan Liang <kan.liang@linux.intel.com>
The userspace RDPMC usage never works for large PEBS since the large PEBS is introduced by commit b8241d20699e ("perf/x86/intel: Implement batched PEBS interrupt handling (large PEBS interrupt threshold)")
When the PEBS interrupt threshold is larger than one, there is no way to get exact auto-reload times and value for userspace RDPMC. Disable the userspace RDPMC usage when large PEBS is enabled.
For the PEBS interrupt threshold equals to one, even it's auto-reload event, it doesn't need to disable the userspace RDPMC. It works well.
Fixes: b8241d20699e ("perf/x86/intel: Implement batched PEBS interrupt handling (large PEBS interrupt threshold)") Signed-off-by: Kan Liang <kan.liang@linux.intel.com> --- arch/x86/events/core.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c index 00a6251..9c86e10 100644 --- a/arch/x86/events/core.c +++ b/arch/x86/events/core.c @@ -2117,7 +2117,8 @@ static int x86_pmu_event_init(struct perf_event *event) event->destroy(event); } - if (READ_ONCE(x86_pmu.attr_rdpmc)) + if (READ_ONCE(x86_pmu.attr_rdpmc) && + !(event->hw.flags & PERF_X86_EVENT_FREERUNNING)) event->hw.flags |= PERF_X86_EVENT_RDPMC_ALLOWED; return err; -- 2.7.4
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