When enabled, 'perf stat' will print count deltas, similar to what
'--interval-print' does. However, instead of printing every N
milliseconds, the delta will be output when perf receives a SIGUSR2
signal.
The perf inferior can, e.g. use a function like
void tell_perf(void)
{
kill(getppid(), SIGUSR2);
}
to make perf output the count delta.
Run example:
# ./perf stat -a -P -e cycles &
[1] 7055
# kill -USR2 7055
# time counts unit events
6.987756397 21 085 307 064 cycles
# fg
./perf stat -a -P -e cycles
^C 9.755385729 25 164 351 653 cycles
Signed-off-by: Björn Töpel <[email protected]>
---
tools/perf/builtin-stat.c | 69 ++++++++++++++++++++++++++++++++++++++++-------
1 file changed, 60 insertions(+), 9 deletions(-)
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index ee7ada7..af7dde1 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -61,6 +61,7 @@
#include "util/counts.h"
#include "util/session.h"
#include "util/tool.h"
+#include "util/trigger.h"
#include "asm/bug.h"
#include <stdlib.h>
@@ -130,6 +131,7 @@ static aggr_get_id_t aggr_get_id;
static bool append_file;
static const char *output_name;
static int output_fd;
+static bool polled_interval = false;
struct perf_stat {
bool record;
@@ -148,6 +150,8 @@ static struct perf_stat perf_stat;
static volatile int done = 0;
+static DEFINE_TRIGGER(polled_interval_trigger);
+
static struct perf_stat_config stat_config = {
.aggr_mode = AGGR_GLOBAL,
.scale = true,
@@ -614,10 +618,25 @@ try_again:
perf_evlist__start_workload(evsel_list);
enable_counters();
- if (interval) {
+ if (interval || polled_interval) {
+ struct timespec rem, *req = &ts;
+
while (!waitpid(child_pid, &status, WNOHANG)) {
- nanosleep(&ts, NULL);
- process_interval();
+ int err = nanosleep(req, &rem);
+
+ if (trigger_is_hit(&polled_interval_trigger)) {
+ trigger_ready(&polled_interval_trigger);
+
+ if (err && errno == EINTR)
+ req = &rem;
+
+ process_interval();
+ continue;
+ }
+
+ req = &ts;
+ if (interval)
+ process_interval();
}
}
wait(&status);
@@ -631,11 +650,26 @@ try_again:
if (WIFSIGNALED(status))
psignal(WTERMSIG(status), argv[0]);
} else {
+ struct timespec rem, *req = &ts;
+
enable_counters();
while (!done) {
- nanosleep(&ts, NULL);
- if (interval)
- process_interval();
+ int err = nanosleep(req, &rem);
+ if (interval || polled_interval) {
+ if (trigger_is_hit(&polled_interval_trigger)) {
+ trigger_ready(&polled_interval_trigger);
+
+ if (err && errno == EINTR)
+ req = &rem;
+
+ process_interval();
+ continue;
+ }
+
+ req = &ts;
+ if (interval)
+ process_interval();
+ }
}
}
@@ -1412,7 +1446,7 @@ static void print_footer(void)
static void print_counters(struct timespec *ts, int argc, const char **argv)
{
- int interval = stat_config.interval;
+ int interval = stat_config.interval || polled_interval;
struct perf_evsel *counter;
char buf[64], *prefix = NULL;
@@ -1472,11 +1506,20 @@ static void print_counters(struct timespec *ts, int
argc, const char **argv)
static volatile int signr = -1;
+
+static void polled_interval_signal(int sig __maybe_unused)
+{
+ if (trigger_is_ready(&polled_interval_trigger))
+ trigger_hit(&polled_interval_trigger);
+}
+
static void skip_signal(int signo)
{
- if ((child_pid == -1) || stat_config.interval)
+ if ((child_pid == -1) || stat_config.interval || polled_interval)
done = 1;
+ polled_interval_signal(signo);
+
signr = signo;
/*
* render child_pid harmless
@@ -1580,6 +1623,8 @@ static const struct option stat_options[] = {
"ms to wait before starting measurement after program
start"),
OPT_BOOLEAN(0, "metric-only", &metric_only,
"Only print computed metrics. No raw values"),
+ OPT_BOOLEAN('P', "polled-interval-print", &polled_interval,
+ "print counts when receive SIGUSR2"),
OPT_END()
};
@@ -2368,6 +2413,12 @@ int cmd_stat(int argc, const char **argv, const char
*prefix __maybe_unused)
signal(SIGALRM, skip_signal);
signal(SIGABRT, skip_signal);
+ if (polled_interval) {
+ signal(SIGUSR2, polled_interval_signal);
+ trigger_on(&polled_interval_trigger);
+ trigger_ready(&polled_interval_trigger);
+ }
+
status = 0;
for (run_idx = 0; forever || run_idx < run_count; run_idx++) {
if (run_count != 1 && verbose)
@@ -2381,7 +2432,7 @@ int cmd_stat(int argc, const char **argv, const char
*prefix __maybe_unused)
}
}
- if (!forever && status != -1 && !interval)
+ if (!forever && status != -1 && !interval && !polled_interval)
print_counters(NULL, argc, argv);
if (STAT_RECORD) {
--
2.7.4
