From: Andi Kleen <a...@linux.intel.com>
I had some problems with spurious PMIs, so print the PMU state
on a spurious one. This will not interact well with other NMI users.
Disabled by default, has to be explicitely enabled through sysfs.
Optional, but useful for debugging.
v2: Move to /sys/devices/cpu
Signed-off-by: Andi Kleen <a...@linux.intel.com>
---
arch/x86/kernel/cpu/perf_event.c | 3 +++
arch/x86/kernel/cpu/perf_event.h | 2 ++
arch/x86/kernel/cpu/perf_event_intel.c | 4 ++++
3 files changed, 9 insertions(+), 0 deletions(-)
diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index 87c2ab0..b0f4edd 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -38,6 +38,7 @@
#include "perf_event.h"
struct x86_pmu x86_pmu __read_mostly;
+int print_spurious_pmi __read_mostly;
DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events) = {
.enabled = 1,
@@ -1630,9 +1631,11 @@ static ssize_t set_attr_rdpmc(struct device *cdev,
}
static DEVICE_ATTR(rdpmc, S_IRUSR | S_IWUSR, get_attr_rdpmc, set_attr_rdpmc);
+static DEVICE_INT_ATTR(print_spurious_pmi, 0644, print_spurious_pmi);
static struct attribute *x86_pmu_attrs[] = {
&dev_attr_rdpmc.attr,
+ &dev_attr_print_spurious_pmi.attr.attr,
NULL,
};
diff --git a/arch/x86/kernel/cpu/perf_event.h b/arch/x86/kernel/cpu/perf_event.h
index 2f714f0..002ecc9 100644
--- a/arch/x86/kernel/cpu/perf_event.h
+++ b/arch/x86/kernel/cpu/perf_event.h
@@ -657,3 +657,5 @@ static inline struct intel_shared_regs
*allocate_shared_regs(int cpu)
}
#endif /* CONFIG_CPU_SUP_INTEL */
+
+extern int print_spurious_pmi;
diff --git a/arch/x86/kernel/cpu/perf_event_intel.c
b/arch/x86/kernel/cpu/perf_event_intel.c
index 0b8251a..8b8bb61 100644
--- a/arch/x86/kernel/cpu/perf_event_intel.c
+++ b/arch/x86/kernel/cpu/perf_event_intel.c
@@ -1205,6 +1205,10 @@ again:
goto again;
done:
+ if (!handled && print_spurious_pmi) {
+ pr_debug("Spurious PMI\n");
+ perf_event_print_debug();
+ }
intel_pmu_enable_all(0);
return handled;
}
--
1.7.7.6
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