perf/x86: Don't assume there can be only 4 PEBS events

On Sandy Bridge in non HT mode there are 8 counters available.
Since every counter can write a PEBS record assuming there are
4 max is incorrect. Use the reported counter number -- with an
upper limit for a static array -- instead.

Also I made the warning messages a bit more informational.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1338944211-28275-2-git-send-email-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/kernel/cpu/perf_event.h b/arch/x86/kernel/cpu/perf_event.h
index 23b5710..3df3de9 100644 (file)
--- a/arch/x86/kernel/cpu/perf_event.h
+++ b/arch/x86/kernel/cpu/perf_event.h
@@ -69,7 +69,7 @@ struct amd_nb {
 };
 
 /* The maximal number of PEBS events: */
-#define MAX_PEBS_EVENTS                4
+#define MAX_PEBS_EVENTS                8
 
 /*
  * A debug store configuration.
@@ -378,6 +378,7 @@ struct x86_pmu {
        void            (*drain_pebs)(struct pt_regs *regs);
        struct event_constraint *pebs_constraints;
        void            (*pebs_aliases)(struct perf_event *event);
+       int             max_pebs_events;
 
        /*
         * Intel LBR

diff --git a/arch/x86/kernel/cpu/perf_event_intel.c b/arch/x86/kernel/cpu/perf_event_intel.c
index 187c294..e23e71f 100644 (file)
--- a/arch/x86/kernel/cpu/perf_event_intel.c
+++ b/arch/x86/kernel/cpu/perf_event_intel.c
@@ -1800,6 +1800,8 @@ __init int intel_pmu_init(void)
        x86_pmu.events_maskl            = ebx.full;
        x86_pmu.events_mask_len         = eax.split.mask_length;
 
+       x86_pmu.max_pebs_events         = min_t(unsigned, MAX_PEBS_EVENTS, x86_pmu.num_counters);
+
        /*
         * Quirk: v2 perfmon does not report fixed-purpose events, so
         * assume at least 3 events:

diff --git a/arch/x86/kernel/cpu/perf_event_intel_ds.c b/arch/x86/kernel/cpu/perf_event_intel_ds.c
index 35e2192..026373e 100644 (file)
--- a/arch/x86/kernel/cpu/perf_event_intel_ds.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_ds.c
@@ -620,7 +620,7 @@ static void intel_pmu_drain_pebs_core(struct pt_regs *iregs)
         * Should not happen, we program the threshold at 1 and do not
         * set a reset value.
         */
-       WARN_ON_ONCE(n > 1);
+       WARN_ONCE(n > 1, "bad leftover pebs %d\n", n);
        at += n - 1;
 
        __intel_pmu_pebs_event(event, iregs, at);
@@ -651,10 +651,10 @@ static void intel_pmu_drain_pebs_nhm(struct pt_regs *iregs)
         * Should not happen, we program the threshold at 1 and do not
         * set a reset value.
         */
-       WARN_ON_ONCE(n > MAX_PEBS_EVENTS);
+       WARN_ONCE(n > x86_pmu.max_pebs_events, "Unexpected number of pebs records %d\n", n);
 
        for ( ; at < top; at++) {
-               for_each_set_bit(bit, (unsigned long *)&at->status, MAX_PEBS_EVENTS) {
+               for_each_set_bit(bit, (unsigned long *)&at->status, x86_pmu.max_pebs_events) {
                        event = cpuc->events[bit];
                        if (!test_bit(bit, cpuc->active_mask))
                                continue;
@@ -670,7 +670,7 @@ static void intel_pmu_drain_pebs_nhm(struct pt_regs *iregs)
                        break;
                }
 
-               if (!event || bit >= MAX_PEBS_EVENTS)
+               if (!event || bit >= x86_pmu.max_pebs_events)
                        continue;
 
                __intel_pmu_pebs_event(event, iregs, at);