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authorAlexander Shishkin <alexander.shishkin@linux.intel.com>2015-08-19 17:02:10 +0300
committerIngo Molnar <mingo@kernel.org>2016-05-05 10:16:28 +0200
commit65c7e6f1c4810e9bce935520f44f6d2613cd1b40 (patch)
tree843648e962ce8f25e343fc489d0b6a764a46305c
parentccbebba4c6bfda8e3ef9e431ce2c3d91c5fc5a63 (diff)
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>
-rw-r--r--arch/x86/events/intel/pt.c54
-rw-r--r--arch/x86/events/intel/pt.h6
2 files changed, 60 insertions, 0 deletions
diff --git a/arch/x86/events/intel/pt.c b/arch/x86/events/intel/pt.c
index 2d1ce2c6ac7b..c3a359cf670e 100644
--- a/arch/x86/events/intel/pt.c
+++ b/arch/x86/events/intel/pt.c
@@ -127,9 +127,46 @@ static struct attribute_group pt_format_group = {
.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 @@ static int __init pt_pmu_hw_init(void)
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
diff --git a/arch/x86/events/intel/pt.h b/arch/x86/events/intel/pt.h
index ca6459996d2d..efffa4a09f68 100644
--- a/arch/x86/events/intel/pt.h
+++ b/arch/x86/events/intel/pt.h
@@ -82,6 +82,9 @@ struct topa_entry {
#define PT_CPUID_LEAVES 2
#define PT_CPUID_REGS_NUM 4 /* number of regsters (eax, ebx, ecx, edx) */
+/* TSC to Core Crystal Clock Ratio */
+#define CPUID_TSC_LEAF 0x15
+
enum pt_capabilities {
PT_CAP_max_subleaf = 0,
PT_CAP_cr3_filtering,
@@ -102,6 +105,9 @@ struct pt_pmu {
struct pmu pmu;
u32 caps[PT_CPUID_REGS_NUM * PT_CPUID_LEAVES];
bool vmx;
+ unsigned long max_nonturbo_ratio;
+ unsigned int tsc_art_num;
+ unsigned int tsc_art_den;
};
/**