From daefd0bc0bd28cea2e6b2f3e1a9da005cd4f58fc Mon Sep 17 00:00:00 2001
From: Kan Liang <Kan.liang@intel.com>
Date: Fri, 26 May 2017 12:05:38 -0700
Subject: perf stat: Add support to measure SMI cost
Implementing a new --smi-cost mode in perf stat to measure SMI cost.
During the measurement, the /sys/device/cpu/freeze_on_smi will be set.
The measurement can be done with one counter (unhalted core cycles), and
two free running MSR counters (IA32_APERF and SMI_COUNT).
In practice, the percentages of SMI core cycles should be more useful
than absolute value. So the output will be the percentage of SMI core
cycles and SMI#. metric_only will be set by default.
SMI cycles% = (aperf - unhalted core cycles) / aperf
Here is an example output.
Performance counter stats for 'sudo echo ':
SMI cycles% SMI#
0.1% 1
0.010858678 seconds time elapsed
Users who wants to get the actual value can apply additional
--no-metric-only.
Signed-off-by: Kan Liang <Kan.liang@intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Robert Elliott <elliott@hpe.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1495825538-5230-3-git-send-email-kan.liang@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/builtin-stat.c | 49 +++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 49 insertions(+)
(limited to 'tools/perf/builtin-stat.c')
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index ad9324d1daf9..324363054c3f 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -86,6 +86,7 @@
#define DEFAULT_SEPARATOR " "
#define CNTR_NOT_SUPPORTED "<not supported>"
#define CNTR_NOT_COUNTED "<not counted>"
+#define FREEZE_ON_SMI_PATH "devices/cpu/freeze_on_smi"
static void print_counters(struct timespec *ts, int argc, const char **argv);
@@ -122,6 +123,14 @@ static const char * topdown_attrs[] = {
NULL,
};
+static const char *smi_cost_attrs = {
+ "{"
+ "msr/aperf/,"
+ "msr/smi/,"
+ "cycles"
+ "}"
+};
+
static struct perf_evlist *evsel_list;
static struct target target = {
@@ -137,6 +146,8 @@ static bool null_run = false;
static int detailed_run = 0;
static bool transaction_run;
static bool topdown_run = false;
+static bool smi_cost = false;
+static bool smi_reset = false;
static bool big_num = true;
static int big_num_opt = -1;
static const char *csv_sep = NULL;
@@ -1782,6 +1793,8 @@ static const struct option stat_options[] = {
"Only print computed metrics. No raw values", enable_metric_only),
OPT_BOOLEAN(0, "topdown", &topdown_run,
"measure topdown level 1 statistics"),
+ OPT_BOOLEAN(0, "smi-cost", &smi_cost,
+ "measure SMI cost"),
OPT_END()
};
@@ -2160,6 +2173,39 @@ static int add_default_attributes(void)
return 0;
}
+ if (smi_cost) {
+ int smi;
+
+ if (sysfs__read_int(FREEZE_ON_SMI_PATH, &smi) < 0) {
+ fprintf(stderr, "freeze_on_smi is not supported.\n");
+ return -1;
+ }
+
+ if (!smi) {
+ if (sysfs__write_int(FREEZE_ON_SMI_PATH, 1) < 0) {
+ fprintf(stderr, "Failed to set freeze_on_smi.\n");
+ return -1;
+ }
+ smi_reset = true;
+ }
+
+ if (pmu_have_event("msr", "aperf") &&
+ pmu_have_event("msr", "smi")) {
+ if (!force_metric_only)
+ metric_only = true;
+ err = parse_events(evsel_list, smi_cost_attrs, NULL);
+ } else {
+ fprintf(stderr, "To measure SMI cost, it needs "
+ "msr/aperf/, msr/smi/ and cpu/cycles/ support\n");
+ return -1;
+ }
+ if (err) {
+ fprintf(stderr, "Cannot set up SMI cost events\n");
+ return -1;
+ }
+ return 0;
+ }
+
if (topdown_run) {
char *str = NULL;
bool warn = false;
@@ -2742,6 +2788,9 @@ int cmd_stat(int argc, const char **argv)
perf_stat__exit_aggr_mode();
perf_evlist__free_stats(evsel_list);
out:
+ if (smi_cost && smi_reset)
+ sysfs__write_int(FREEZE_ON_SMI_PATH, 0);
+
perf_evlist__delete(evsel_list);
return status;
}
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