[PATCH 4/4] perf_events: x86: Remove spurious counter reset from x86_pmu_enable()

[Peter Zijlstra]

At enable time the counter might still have a ->idx pointing to a
previously occupied location that might now be taken by another event.
Resetting the counter at that location with data from this event will
destroy the other counter's count.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
---
 arch/x86/kernel/cpu/perf_event.c |    3 ---
 1 file changed, 3 deletions(-)

Index: linux-2.6/arch/x86/kernel/cpu/perf_event.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/cpu/perf_event.c
+++ linux-2.6/arch/x86/kernel/cpu/perf_event.c
@@ -1769,9 +1769,6 @@ static int x86_pmu_enable(struct perf_ev
 	cpuc->n_events = n;
 	cpuc->n_added  = n - n0;
 
-	if (hwc->idx != -1)
-		x86_perf_event_set_period(event, hwc, hwc->idx);
-
 	return 0;
 }
 

-- 

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