[PATCH V3 2/5] perf/x86: introduce read function for x86_pmu

[kan . liang]

From: Kan Liang <kan.li...@linux.intel.com>

Large PEBS needs to be specially handled in event count read.

Signed-off-by: Kan Liang <kan.li...@linux.intel.com>
---
 arch/x86/events/core.c       | 2 ++
 arch/x86/events/perf_event.h | 1 +
 2 files changed, 3 insertions(+)

diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index 140d332..acd7ffc 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -1884,6 +1884,8 @@ early_initcall(init_hw_perf_events);
 
 static inline void x86_pmu_read(struct perf_event *event)
 {
+       if (x86_pmu.read)
+               return x86_pmu.read(event);
        x86_perf_event_update(event);
 }
 
diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h
index 8e4ea143..805400b 100644
--- a/arch/x86/events/perf_event.h
+++ b/arch/x86/events/perf_event.h
@@ -519,6 +519,7 @@ struct x86_pmu {
        void            (*disable)(struct perf_event *);
        void            (*add)(struct perf_event *);
        void            (*del)(struct perf_event *);
+       void            (*read)(struct perf_event *event);
        int             (*hw_config)(struct perf_event *event);
        int             (*schedule_events)(struct cpu_hw_events *cpuc, int n, 
int *assign);
        unsigned        eventsel;
-- 
2.7.4