Messages in this thread Patch in this message | | | From | Andi Kleen <> | Subject | [PATCH 18/32] perf, x86: Support for printing PMU state on spurious PMIs v3 | Date | Tue, 30 Oct 2012 17:34:09 -0700 |
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From: Andi Kleen <ak@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 v3: Print in more cases Signed-off-by: Andi Kleen <ak@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 | 11 ++++++----- 3 files changed, 11 insertions(+), 5 deletions(-)
diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c index ec3c549..57bb4ce 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, @@ -1758,9 +1759,11 @@ 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 d55e502..2ef5b20 100644 --- a/arch/x86/kernel/cpu/perf_event.h +++ b/arch/x86/kernel/cpu/perf_event.h @@ -664,3 +664,5 @@ 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 20caf0a..dc2f2a1 100644 --- a/arch/x86/kernel/cpu/perf_event_intel.c +++ b/arch/x86/kernel/cpu/perf_event_intel.c @@ -1146,11 +1146,8 @@ static int intel_pmu_handle_irq(struct pt_regs *regs) intel_pmu_disable_all(); handled = intel_pmu_drain_bts_buffer(); status = intel_pmu_get_status(); - if (!status) { - intel_pmu_enable_all(0); - return handled; - } - + if (!status) + goto done; loops = 0; again: intel_pmu_ack_status(status); @@ -1210,6 +1207,10 @@ 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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