perf, x86: P4 PMU -- handle unflagged events

[safe/jmp/linux-2.6] / arch / x86 / kernel / cpu / perf_event_p4.c

diff --git a/arch/x86/kernel/cpu/perf_event_p4.c b/arch/x86/kernel/cpu/perf_event_p4.c
index 424fc8d..02f0728 100644 (file)
--- a/arch/x86/kernel/cpu/perf_event_p4.c
+++ b/arch/x86/kernel/cpu/perf_event_p4.c
@@ -465,15 +465,21 @@ out:
        return rc;
 }
 
-static inline void p4_pmu_clear_cccr_ovf(struct hw_perf_event *hwc)
+static inline int p4_pmu_clear_cccr_ovf(struct hw_perf_event *hwc)
 {
-       unsigned long dummy;
+       int overflow = 0;
+       u32 low, high;
 
-       rdmsrl(hwc->config_base + hwc->idx, dummy);
-       if (dummy & P4_CCCR_OVF) {
+       rdmsr(hwc->config_base + hwc->idx, low, high);
+
+       /* we need to check high bit for unflagged overflows */
+       if ((low & P4_CCCR_OVF) || (high & (1 << 31))) {
+               overflow = 1;
                (void)checking_wrmsrl(hwc->config_base + hwc->idx,
-                       ((u64)dummy) & ~P4_CCCR_OVF);
+                       ((u64)low) & ~P4_CCCR_OVF);
        }
+
+       return overflow;
 }
 
 static inline void p4_pmu_disable_event(struct perf_event *event)
@@ -584,21 +590,15 @@ static int p4_pmu_handle_irq(struct pt_regs *regs)
 
                WARN_ON_ONCE(hwc->idx != idx);
 
-               /*
-                * FIXME: Redundant call, actually not needed
-                * but just to check if we're screwed
-                */
-               p4_pmu_clear_cccr_ovf(hwc);
+               /* it might be unflagged overflow */
+               handled = p4_pmu_clear_cccr_ovf(hwc);
 
                val = x86_perf_event_update(event);
-               if (val & (1ULL << (x86_pmu.cntval_bits - 1)))
+               if (!handled && (val & (1ULL << (x86_pmu.cntval_bits - 1))))
                        continue;
 
-               /*
-                * event overflow
-                */
-               handled         = 1;
-               data.period     = event->hw.last_period;
+               /* event overflow for sure */
+               data.period = event->hw.last_period;
 
                if (!x86_perf_event_set_period(event))
                        continue;