perf/x86/intel/pt: Export CPU frequency ratios needed by PT decoders
Intel PT decoders need access to various bits of timing related
information to be able to correctly decode timing packets from a PT
stream (MTC and CBR packets). This patch exports all the necessary
bits as sysfs attributes for the sake of consistency:
* max_nonturbo_ratio: ratio between the invariant TSC and base clock;
* tsc_art_ratio: TSC to core crystal clock ratio (also available as CPUID.15H).
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: vince@deater.net
Link: http://lkml.kernel.org/r/87zisdvibe.fsf@ashishki-desk.ger.corp.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/arch/x86/events/intel/pt.c b/arch/x86/events/intel/pt.c
index 2d1ce2c..c3a359c 100644
--- a/arch/x86/events/intel/pt.c
+++ b/arch/x86/events/intel/pt.c
@@ -127,9 +127,46 @@
.attrs = pt_formats_attr,
};
+static ssize_t
+pt_timing_attr_show(struct device *dev, struct device_attribute *attr,
+ char *page)
+{
+ struct perf_pmu_events_attr *pmu_attr =
+ container_of(attr, struct perf_pmu_events_attr, attr);
+
+ switch (pmu_attr->id) {
+ case 0:
+ return sprintf(page, "%lu\n", pt_pmu.max_nonturbo_ratio);
+ case 1:
+ return sprintf(page, "%u:%u\n",
+ pt_pmu.tsc_art_num,
+ pt_pmu.tsc_art_den);
+ default:
+ break;
+ }
+
+ return -EINVAL;
+}
+
+PMU_EVENT_ATTR(max_nonturbo_ratio, timing_attr_max_nonturbo_ratio, 0,
+ pt_timing_attr_show);
+PMU_EVENT_ATTR(tsc_art_ratio, timing_attr_tsc_art_ratio, 1,
+ pt_timing_attr_show);
+
+static struct attribute *pt_timing_attr[] = {
+ &timing_attr_max_nonturbo_ratio.attr.attr,
+ &timing_attr_tsc_art_ratio.attr.attr,
+ NULL,
+};
+
+static struct attribute_group pt_timing_group = {
+ .attrs = pt_timing_attr,
+};
+
static const struct attribute_group *pt_attr_groups[] = {
&pt_cap_group,
&pt_format_group,
+ &pt_timing_group,
NULL,
};
@@ -142,6 +179,23 @@
int ret;
long i;
+ rdmsrl(MSR_PLATFORM_INFO, reg);
+ pt_pmu.max_nonturbo_ratio = (reg & 0xff00) >> 8;
+
+ /*
+ * if available, read in TSC to core crystal clock ratio,
+ * otherwise, zero for numerator stands for "not enumerated"
+ * as per SDM
+ */
+ if (boot_cpu_data.cpuid_level >= CPUID_TSC_LEAF) {
+ u32 eax, ebx, ecx, edx;
+
+ cpuid(CPUID_TSC_LEAF, &eax, &ebx, &ecx, &edx);
+
+ pt_pmu.tsc_art_num = ebx;
+ pt_pmu.tsc_art_den = eax;
+ }
+
if (boot_cpu_has(X86_FEATURE_VMX)) {
/*
* Intel SDM, 36.5 "Tracing post-VMXON" says that