@@ -65,6 +65,25 @@ static int shutdown;
static int tracelimit;
+static int trace_marker = -1;
+
+static void trace_log(const char *s)
+{
+ write(trace_marker, s, strlen(s));
+}
+
+
+static int trace_switch = -1;
+
+static void trace_on(void)
+{
+ write(trace_switch, "1", 1);
+}
+
+static void trace_off(void)
+{
+ write(trace_switch, "0", 1);
+}
/*
* signal thread
*
@@ -99,8 +118,10 @@ void *signalthread(void *param)
long diff;
int sigs;
+ trace_log("Before sigwait\n");
if (sigwait(&sigset, &sigs) < 0)
goto out;
+ trace_log("After sigwait\n");
clock_gettime(CLOCK_MONOTONIC, &after);
@@ -108,12 +129,17 @@ void *signalthread(void *param)
* If it is the first thread, sleep after every 16
* round trips.
*/
- if (!par->id && !(stat->cycles & 0x0F))
+ if (!par->id && !(stat->cycles & 0x0F)) {
+ trace_log("Before sleep\n");
usleep(10000);
+ trace_log("After sleep\n");
+ }
/* Get current time */
clock_gettime(CLOCK_MONOTONIC, &now);
+ trace_log("Before phtread_kill\n");
pthread_kill(stat->tothread, SIGUSR1);
+ trace_log("After phtread_kill\n");
/* Skip the first cycle */
if (first) {
@@ -136,6 +162,7 @@ void *signalthread(void *param)
stat->interrupted = 1;
stopped++;
shutdown++;
+ trace_log("trace_limit\n");
}
stat->act = diff;
stat->cycles++;
@@ -154,6 +181,7 @@ void *signalthread(void *param)
stat->threadstarted = -1;
+ trace_off();
return NULL;
}
@@ -242,6 +270,7 @@ static void process_options(int argc, char *argv[])
static void sighand(int sig)
{
shutdown = 1;
+ trace_off();
}
static void print_stat(struct thread_param *par, int index, int verbose)
@@ -287,6 +316,18 @@ int main(int argc, char **argv)
goto out;
}
+ trace_marker = open("/sys/kernel/debug/tracing/trace_marker", O_WRONLY);
+ if (trace_marker < 0) {
+ printf("Failed to open trace_marker: %m\n");
+ exit(1);
+ }
+
+ trace_switch = open("/sys/kernel/debug/tracing/tracing_on", O_WRONLY);
+ if (trace_switch < 0) {
+ printf("Failed to open trace_marker: %m\n");
+ exit(1);
+ }
+
sigemptyset(&sigset);
sigaddset(&sigset, signum);
sigprocmask(SIG_BLOCK, &sigset, NULL);
@@ -305,6 +346,7 @@ int main(int argc, char **argv)
if (!stat)
goto outpar;
+ trace_on();
for (i = 0; i < num_threads; i++) {
if (verbose) {
stat[i].values = calloc(VALBUF_SIZE, sizeof(long));
@@ -348,7 +390,9 @@ int main(int argc, char **argv)
stat[i].tothread = stat[0].thread;
break;
}
+ trace_log("Main phtread_kill\n");
pthread_kill(stat[0].thread, signum);
+ trace_log("Main phtread_kill post\n");
while (!shutdown) {
char lavg[256];
@@ -374,6 +418,7 @@ int main(int argc, char **argv)
}
ret = 0;
outall:
+ trace_off();
shutdown = 1;
usleep(50000);
if (quiet)
This isn't intended for merging. This is just for Daniel to help him with tracing. The intention: - TH0 waits for a signal - TH1 waits for a signal - main thread sends a signal to TH1 - TH0 wakes up, sends a signal to TH1, waits for SIGNAL - TH1 wakes up, sends a signal to TH0, waits for SIGNAL - loop begin. - TH0 wakes up, measures the delay between sending a signal and receiving a signal. Sends a signal to TH1. - TH1 wakes up, sends a signal to TH0, waits for SIGNAL - loop end. There is nothing that pins the two threads. So the scheduler might be busy to move them from CPU to another. Pinning everything to one CPU might make a difference. taskset -c 1 ~/signaltest -m -p 98 -b 400 Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> --- src/signaltest/signaltest.c | 47 ++++++++++++++++++++++++++++++++++++- 1 file changed, 46 insertions(+), 1 deletion(-)