int main(int argc, char *argv[])
{
int i, j, k, err;
unsigned long long delta;
unsigned long long max, min;
struct sched_param param;
stats_container_t dat;
stats_container_t hist;
stats_quantiles_t quantiles;
stats_record_t rec;
struct timespec *start_data;
struct timespec *stop_data;
if (stats_cmdline(argc, argv) < 0) {
printf("usage: %s help\n", argv[0]);
exit(1);
}
if (iterations < MIN_ITERATION) {
iterations = MIN_ITERATION;
printf("user \"iterations\" value is too small (use: %d)\n",
iterations);
}
stats_container_init(&dat, iterations);
stats_container_init(&hist, HIST_BUCKETS);
stats_quantiles_init(&quantiles, (int)log10(iterations));
setup();
mlockall(MCL_CURRENT | MCL_FUTURE);
start_data = calloc(iterations, sizeof(struct timespec));
if (start_data == NULL) {
printf("Memory allocation Failed (too many Iteration: %d)\n",
iterations);
exit(1);
}
stop_data = calloc(iterations, sizeof(struct timespec));
if (stop_data == NULL) {
printf("Memory allocation Failed (too many Iteration: %d)\n",
iterations);
free(start_data);
exit(1);
}
/* switch to SCHED_FIFO 99 */
param.sched_priority = sched_get_priority_max(SCHED_FIFO);
err = sched_setscheduler(0, SCHED_FIFO, ¶m);
/* Check that the user has the appropriate privileges */
if (err) {
if (errno == EPERM) {
fprintf(stderr,
"This program runs with a scheduling policy of SCHED_FIFO at priority %d\n",
param.sched_priority);
fprintf(stderr,
"You don't have the necessary privileges to create such a real-time process.\n");
} else {
fprintf(stderr, "Failed to set scheduler, errno %d\n",
errno);
}
exit(1);
}
printf("\n----------------------\n");
printf("Gettimeofday() Latency\n");
printf("----------------------\n");
printf("Iterations: %d\n\n", iterations);
/* collect iterations pairs of gtod calls */
max = min = 0;
if (latency_threshold) {
latency_trace_enable();
latency_trace_start();
}
/* This loop runs for a long time, hence can cause soft lockups.
Calling sleep periodically avoids this. */
for (i = 0; i < (iterations / 10000); i++) {
for (j = 0; j < 10000; j++) {
k = (i * 10000) + j;
clock_gettime(CLOCK_MONOTONIC, &start_data[k]);
clock_gettime(CLOCK_MONOTONIC, &stop_data[k]);
}
usleep(1000);
}
for (i = 0; i < iterations; i++) {
delta = timespec_subtract(&start_data[i], &stop_data[i]);
rec.x = i;
rec.y = delta;
stats_container_append(&dat, rec);
if (i == 0 || delta < min)
min = delta;
if (delta > max)
max = delta;
if (latency_threshold && delta > latency_threshold)
break;
}
if (latency_threshold) {
latency_trace_stop();
if (i != iterations) {
printf
("Latency threshold (%lluus) exceeded at iteration %d\n",
latency_threshold, i);
latency_trace_print();
stats_container_resize(&dat, i + 1);
}
}
stats_hist(&hist, &dat);
stats_container_save(filenames[SCATTER_FILENAME], titles[SCATTER_TITLE],
labels[SCATTER_LABELX], labels[SCATTER_LABELY],
&dat, "points");
stats_container_save(filenames[HIST_FILENAME], titles[HIST_TITLE],
labels[HIST_LABELX], labels[HIST_LABELY], &hist,
"steps");
/* report on deltas */
printf("Min: %llu ns\n", min);
printf("Max: %llu ns\n", max);
printf("Avg: %.4f ns\n", stats_avg(&dat));
printf("StdDev: %.4f ns\n", stats_stddev(&dat));
printf("Quantiles:\n");
stats_quantiles_calc(&dat, &quantiles);
stats_quantiles_print(&quantiles);
stats_container_free(&dat);
stats_container_free(&hist);
stats_quantiles_free(&quantiles);
return 0;
}
void *periodic_thread(void *arg)
{
int i;
nsec_t delay, avg_delay = 0, start_delay, min_delay = -1ULL, max_delay = 0;
int failures = 0;
nsec_t next = 0, now = 0, sched_delta = 0, delta = 0, prev = 0, iter_start;
/* wait for the specified start time */
rt_nanosleep_until(start);
now = rt_gettime();
start_delay = (now - start)/NS_PER_US;
iter_start = next = now;
debug(DBG_INFO, "ITERATION DELAY(US) MAX_DELAY(US) FAILURES\n");
debug(DBG_INFO, "--------- --------- ------------- --------\n");
if (latency_threshold) {
latency_trace_enable();
latency_trace_start();
}
for (i = 0; i < iterations; i++) {
/* wait for the period to start */
next += period;
prev = now;
now = rt_gettime();
if (next < now) {
printf("\nPERIOD MISSED!\n");
printf(" scheduled delta: %8llu us\n", sched_delta/1000);
printf(" actual delta: %8llu us\n", delta/1000);
printf(" latency: %8llu us\n", (delta-sched_delta)/1000);
printf("---------------------------------------\n");
printf(" previous start: %8llu us\n", (prev-iter_start)/1000);
printf(" now: %8llu us\n", (now-iter_start)/1000);
printf(" scheduled start: %8llu us\n", (next-iter_start)/1000);
printf("next scheduled start is in the past!\n");
ret = 1;
break;
}
sched_delta = next - now; /* how long we should sleep */
delta = 0;
do {
nsec_t new_now;
rt_nanosleep(next - now);
new_now = rt_gettime();
delta += new_now - now; /* how long we did sleep */
now = new_now;
} while (now < next);
/* start of period */
delay = (now - iter_start - (nsec_t)(i+1)*period)/NS_PER_US;
rec.x = i;
rec.y = delay;
stats_container_append(&dat, rec);
if (delay < min_delay)
min_delay = delay;
if (delay > max_delay)
max_delay = delay;
if (delay > pass_criteria) {
failures++;
ret = 1;
}
avg_delay += delay;
if (latency_threshold && delay > latency_threshold)
break;
/* continuous status ticker */
debug(DBG_INFO, "%9i %9llu %13llu %8i\r", i, delay, max_delay, failures);
fflush(stdout);
busy_work_ms(load_ms);
}
if (latency_threshold) {
latency_trace_stop();
if (i != iterations) {
printf("Latency threshold (%lluus) exceeded at iteration %d\n",
latency_threshold, i);
latency_trace_print();
stats_container_resize(&dat, i+1);
}
}
/* save samples before the quantile calculation messes things up! */
stats_hist(&hist, &dat);
stats_container_save("samples", "Periodic Scheduling Latency Scatter Plot",\
"Iteration", "Latency (us)", &dat, "points");
stats_container_save("hist", "Periodic Scheduling Latency Histogram",\
"Latency (us)", "Samples", &hist, "steps");
avg_delay /= i;
printf("\n\n");
printf("Start: %4llu us: %s\n", start_delay,
start_delay < pass_criteria ? "PASS" : "FAIL");
printf("Min: %4llu us: %s\n", min_delay,
min_delay < pass_criteria ? "PASS" : "FAIL");
printf("Max: %4llu us: %s\n", max_delay,
max_delay < pass_criteria ? "PASS" : "FAIL");
printf("Avg: %4llu us: %s\n", avg_delay,
avg_delay < pass_criteria ? "PASS" : "FAIL");
printf("StdDev: %.4f us\n", stats_stddev(&dat));
printf("Quantiles:\n");
stats_quantiles_calc(&dat, &quantiles);
stats_quantiles_print(&quantiles);
printf("Failed Iterations: %d\n", failures);
return NULL;
}
void *signal_receiving_thread(void *arg)
{
int i, ret, sig;
long delta;
long max, min;
sigset_t set, oset;
stats_container_t dat;
stats_container_t hist;
stats_quantiles_t quantiles;
stats_record_t rec;
stats_container_init(&dat, ITERATIONS);
stats_container_init(&hist, HIST_BUCKETS);
stats_quantiles_init(&quantiles, (int)log10(ITERATIONS));
debug(DBG_DEBUG, "Signal receiving thread running\n");
if ((sigaddset(&set, SIGNALNUMBER))) {
perror("sigaddset:");
exit(1);
}
if ((ret = pthread_sigmask(SIG_BLOCK, &set, &oset))) {
printf("pthread_sigmask returned %d\n", ret);
exit(1);
}
/* Let the sending thread know that receiver is ready */
atomic_set(1, &flag);
debug(DBG_DEBUG, "Signal receiving thread ready to receive\n");
if (latency_threshold) {
latency_trace_enable();
latency_trace_start();
}
/* Warm up */
for (i = 0; i < 5; i++) {
sigwait(&set, &sig);
atomic_set(1, &flag);
}
max = min = 0;
fail = 0;
debug(DBG_INFO, "\n\n");
for (i = 0; i < ITERATIONS; i++) {
sigwait(&set, &sig);
end = rt_gettime();
delta = (end - begin)/NS_PER_US;
rec.x = i;
rec.y = delta;
stats_container_append(&dat, rec);
if (i == 0 || delta < min)
min = delta;
if (delta > max)
max = delta;
if (delta > pass_criteria) fail++;
debug(DBG_INFO, "Iteration %d: Took %ld us. Max = %ld us, "
"Min = %ld us\n", i, delta, max, min);
fflush(stdout);
buffer_print();
if (latency_threshold && (delta > latency_threshold)) {
atomic_set(2, &flag);
break;
}
atomic_set(1, &flag);
}
if (latency_threshold) {
latency_trace_stop();
if (i != ITERATIONS) {
printf("Latency threshold (%luus) exceeded at iteration %d\n",
latency_threshold, i);
fflush(stdout);
buffer_print();
latency_trace_print();
stats_container_resize(&dat, i + 1);
}
}
stats_hist(&hist, &dat);
stats_container_save("samples", "pthread_kill Latency Scatter Plot",
"Iteration", "Latency (us)", &dat, "points");
stats_container_save("hist", "pthread_kill Latency Histogram",
"Latency (us)", "Samples", &hist, "steps");
printf("\n");
printf("Min: %lu us\n", stats_min(&dat));
printf("Max: %lu us\n", stats_max(&dat));
printf("Avg: %.4f us\n", stats_avg(&dat));
printf("StdDev: %.4f us\n", stats_stddev(&dat));
printf("Quantiles:\n");
stats_quantiles_calc(&dat, &quantiles);
stats_quantiles_print(&quantiles);
printf("Failures: %d\n", fail);
printf("Criteria: Time < %d us\n", (int)pass_criteria);
printf("Result: %s", fail ? "FAIL" : "PASS");
printf("\n\n");
return NULL;
}
