From: Andi Kleen <a...@linux.intel.com>
Add basic plumbing for TopDown in perf stat
Add a new --topdown options to enable events.
When --topdown is specified set up events for all topdown
events supported by the kernel.
Add topdown-* as a special case to the event parser, as is
needed for all events containing -.
The actual code to compute the metrics is in follow-on patches.
Signed-off-by: Andi Kleen <a...@linux.intel.com>
---
tools/perf/Documentation/perf-stat.txt | 8 +++
tools/perf/builtin-stat.c | 124 ++++++++++++++++++++++++++++++++-
tools/perf/util/parse-events.l | 1 +
3 files changed, 131 insertions(+), 2 deletions(-)
diff --git a/tools/perf/Documentation/perf-stat.txt
b/tools/perf/Documentation/perf-stat.txt
index 47469ab..86c03e9 100644
--- a/tools/perf/Documentation/perf-stat.txt
+++ b/tools/perf/Documentation/perf-stat.txt
@@ -158,6 +158,14 @@ filter out the startup phase of the program, which is
often very different.
Print statistics of transactional execution if supported.
+--topdown::
+
+Print top down level 1 metrics if supported by the CPU. This allows to
+determine bottle necks in the CPU pipeline for CPU bound workloads,
+by breaking it down into frontend bound, backend bound, bad speculation
+and retiring. Specifying the option multiple times shows metrics even
+if the don't cross a threshold.
+
EXAMPLES
--------
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 2590c75..a83f26f 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -93,6 +93,15 @@ static const char * transaction_limited_attrs = {
"}"
};
+static const char * topdown_attrs[] = {
+ "topdown-total-slots",
+ "topdown-fetch-bubbles",
+ "topdown-slots-retired",
+ "topdown-recovery-bubbles",
+ "topdown-slots-issued",
+ NULL,
+};
+
static struct perf_evlist *evsel_list;
static struct target target = {
@@ -105,6 +114,7 @@ static volatile pid_t child_pid
= -1;
static bool null_run = false;
static int detailed_run = 0;
static bool transaction_run;
+static int topdown_run = 0;
static bool big_num = true;
static int big_num_opt = -1;
static const char *csv_sep = NULL;
@@ -735,7 +745,8 @@ static void printout(int id, int nr, struct perf_evsel
*counter, double uval,
first_shadow_cpu(counter, id),
pm,
nl,
- &os);
+ &os,
+ topdown_run);
if (!csv_output) {
print_noise(counter, noise);
@@ -1093,12 +1104,90 @@ static int perf_stat_init_aggr_mode(void)
return 0;
}
+static void filter_events(const char **attr, char **str, bool use_group)
+{
+ int off = 0;
+ int i;
+ int len = 0;
+ char *s;
+
+ for (i = 0; attr[i]; i++) {
+ if (pmu_have_event("cpu", attr[i])) {
+ len += strlen(attr[i]) + 1;
+ attr[i - off] = attr[i];
+ } else
+ off++;
+ }
+ attr[i - off] = NULL;
+
+ *str = malloc(len + 1 + 2);
+ if (!*str)
+ return;
+ s = *str;
+ if (i - off == 0) {
+ *s = 0;
+ return;
+ }
+ if (use_group)
+ *s++ = '{';
+ for (i = 0; attr[i]; i++) {
+ strcpy(s, attr[i]);
+ s += strlen(s);
+ *s++ = ',';
+ }
+ if (use_group) {
+ s[-1] = '}';
+ *s = 0;
+ } else
+ s[-1] = 0;
+}
+
+/* Caller must free result */
+static char *sysctl_read(const char *fn)
+{
+ int n;
+ char *line = NULL;
+ size_t linelen = 0;
+ FILE *f = fopen(fn, "r");
+ if (!f)
+ return NULL;
+ n = getline(&line, &linelen, f);
+ fclose(f);
+ if (n > 0)
+ return line;
+ free(line);
+ return NULL;
+}
+
+/*
+ * Check whether we can use a group for top down.
+ * Without a group may get bad results.
+ */
+static bool check_group(bool *warn)
+{
+ char *v = sysctl_read("/proc/sys/kernel/nmi_watchdog");
+ int n;
+
+ *warn = false;
+ if (v) {
+ bool res = sscanf(v, "%d", &n) == 1 && n != 0;
+ free(v);
+ if (res) {
+ *warn = true;
+ return false;
+ }
+ return true;
+ }
+ return false; /* Don't know, so don't use group */
+}
+
/*
* Add default attributes, if there were no attributes specified or
* if -d/--detailed, -d -d or -d -d -d is used:
*/
static int add_default_attributes(void)
{
+ int err;
struct perf_event_attr default_attrs[] = {
{ .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_TASK_CLOCK
},
@@ -1211,7 +1300,6 @@ static int add_default_attributes(void)
return 0;
if (transaction_run) {
- int err;
if (pmu_have_event("cpu", "cycles-ct") &&
pmu_have_event("cpu", "el-start"))
err = parse_events(evsel_list, transaction_attrs, NULL);
@@ -1224,6 +1312,36 @@ static int add_default_attributes(void)
return 0;
}
+ if (topdown_run) {
+ char *str = NULL;
+ bool warn;
+
+ filter_events(topdown_attrs, &str, check_group(&warn));
+ if (topdown_attrs[0] && str) {
+ if (warn)
+ fprintf(stderr,
+ "nmi_watchdog enabled with topdown. May give wrong results.\n"
+ "Disable with echo 0 > /proc/sys/kernel/nmi_watchdog\n");
+ err = parse_events(evsel_list, str, NULL);
+ if (err) {
+ fprintf(stderr,
+ "Cannot set up top down events %s:
%d\n",
+ str, err);
+ free(str);
+ return -1;
+ }
+ } else {
+ fprintf(stderr, "System does not support topdown\n");
+ return -1;
+ }
+ free(str);
+ /*
+ * Right now combining with the other attributes breaks group
+ * semantics.
+ */
+ return 0;
+ }
+
if (!evsel_list->nr_entries) {
if (perf_evlist__add_default_attrs(evsel_list, default_attrs) <
0)
return -1;
@@ -1260,6 +1378,8 @@ int cmd_stat(int argc, const char **argv, const char
*prefix __maybe_unused)
const struct option options[] = {
OPT_BOOLEAN('T', "transaction", &transaction_run,
"hardware transaction statistics"),
+ OPT_INCR(0, "topdown", &topdown_run,
+ "measure topdown level 1 statistics"),
OPT_CALLBACK('e', "event", &evsel_list, "event",
"event selector. use 'perf list' to list available events",
parse_events_option),
diff --git a/tools/perf/util/parse-events.l b/tools/perf/util/parse-events.l
index f542750..a3b9903 100644
--- a/tools/perf/util/parse-events.l
+++ b/tools/perf/util/parse-events.l
@@ -239,6 +239,7 @@ cycles-ct { return
str(yyscanner, PE_KERNEL_PMU_EVENT); }
cycles-t { return str(yyscanner,
PE_KERNEL_PMU_EVENT); }
mem-loads { return str(yyscanner,
PE_KERNEL_PMU_EVENT); }
mem-stores { return str(yyscanner,
PE_KERNEL_PMU_EVENT); }
+topdown-[a-z-]+ { return str(yyscanner,
PE_KERNEL_PMU_EVENT); }
L1-dcache|l1-d|l1d|L1-data |
L1-icache|l1-i|l1i|L1-instruction |
--
2.4.3
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