static void event(void *cookie)
{
int err;
err = rt_task_set_periodic(NULL,
TM_NOW,
rt_timer_ns2ticks(sampling_period));
if (err) {
warning("failed to enter periodic timing (%s)\n",
symerror(err));
return;
}
for (;;) {
err = rt_task_wait_period(NULL);
if (err) {
if (err != -ETIMEDOUT)
exit(EXIT_FAILURE);
late++;
}
switch_count++;
err = rt_sem_broadcast(&switch_sem);
switch_tsc = rt_timer_tsc();
if (err) {
if (err != -EIDRM && err != -EINVAL)
warning("failed to broadcast semaphore (%s)\n",
symerror(err));
break;
}
}
}
void __traceobj_check_warn(struct traceobj *trobj,
const char *file, int line,
int received, int expected)
{
dump_marks_on_error(trobj);
warning("wrong return status:\n %s:%d => %s (want %s)", file, line,
symerror(received > 0 ? -received : received),
symerror(expected > 0 ? -expected : expected));
}
void backtrace_dump(struct backtrace_data *btd)
{
struct error_frame *ef;
FILE *tracefp = stderr;
int n = 0;
if (btd == NULL)
btd = &main_btd;
SIGSAFE_LOCK_ENTRY(&__printlock);
if (btd->inner == NULL)
goto no_error;
fprintf(tracefp,
"%s\n[ ERROR BACKTRACE: thread %s ]\n\n",
dashes, btd->name);
for (ef = btd->inner; ef; ef = ef->next, n++)
fprintf(tracefp, "%s #%-2d %s in %s(), %s:%d\n",
ef->next ? " " : "=>",
n, symerror(ef->retval),
ef->fn, ef->file, ef->lineno);
fputs(dashes, tracefp);
fputc('\n', tracefp);
fflush(tracefp);
flush_backtrace(btd);
no_error:
SIGSAFE_LOCK_EXIT(&__printlock);
}
int main(int argc, char *const *argv)
{
int err, c;
copperplate_init(&argc, &argv);
while ((c = getopt(argc, argv, "hp:n:i:")) != EOF)
switch (c) {
case 'h':
/* ./switch --h[istogram] */
do_histogram = 1;
break;
case 'p':
sampling_period = atoi(optarg) * 1000;
break;
case 'n':
nsamples = atoi(optarg);
break;
case 'i':
warmup = atoi(optarg);
break;
default:
fprintf(stderr, "usage: switch [options]\n"
"\t-h - enable histogram\n"
"\t-p <period_us> - timer period\n"
"\t-n <samples> - number of samples to collect\n"
"\t-i <samples> - number of _first_ samples to ignore\n");
exit(2);
}
if (sampling_period == 0)
sampling_period = 100000; /* ns */
if (nsamples <= 0) {
warning("disregarding -n <%lld>, using -n <100000> "
"samples\n", nsamples);
nsamples = 100000;
}
signal(SIGINT, SIG_IGN);
signal(SIGTERM, SIG_IGN);
setlinebuf(stdout);
mlockall(MCL_CURRENT|MCL_FUTURE);
printf("== Sampling period: %llu us\n", sampling_period / 1000);
printf("== Do not interrupt this program\n");
err = rt_task_create(&worker_task, "worker", 0, 98, 0);
if (err) {
warning("failed to create WORKER task (%s)\n",
symerror(err));
return 1;
}
err = rt_task_start(&worker_task, &worker, NULL);
if (err) {
warning("failed to start WORKER task (%s)\n",
symerror(err));
return 1;
}
err = rt_task_create(&event_task, "event", 0, 99, 0);
if (err) {
warning("failed to create EVENT task (%s)\n",
symerror(err));
return 1;
}
err = rt_task_start(&event_task, &event, NULL);
if (err) {
warning("failed to start EVENT task (%s)\n",
symerror(err));
return 1;
}
for (;;)
pause();
return 0;
}
static void worker(void *cookie)
{
long long minj = 10000000, maxj = -10000000, dt, sumj = 0;
unsigned long long count = 0;
int err, n;
err = rt_sem_create(&switch_sem, "dispsem", 0, S_FIFO);
if (err) {
warning("failed to create semaphore (%s)\n",
symerror(err));
return;
}
for (n = 0; n < nsamples; n++) {
err = rt_sem_p(&switch_sem, TM_INFINITE);
if (err) {
if (err != -EIDRM && err != -EINVAL)
warning("failed to pend on semaphore (%s)\n",
symerror(err));
exit(EXIT_FAILURE);
}
dt = (long) (rt_timer_tsc() - switch_tsc);
if (switch_count - count > 1) {
lost += switch_count - count;
count = switch_count;
continue;
}
if (++count < warmup)
continue;
if (dt > maxj)
maxj = dt;
if (dt < minj)
minj = dt;
sumj += dt;
if (do_histogram)
add_histogram(dt);
}
rt_sem_delete(&switch_sem);
minjitter = minj;
maxjitter = maxj;
avgjitter = sumj / n;
printf("RTH|%12s|%12s|%12s|%12s\n",
"lat min", "lat avg", "lat max", "lost");
printf("RTD|%12.3f|%12.3f|%12.3f|%12lld\n",
rt_timer_tsc2ns(minjitter) / 1000.0,
rt_timer_tsc2ns(avgjitter) / 1000.0,
rt_timer_tsc2ns(maxjitter) / 1000.0, lost);
if (late)
printf("LATE: %d\n", late);
if (do_histogram)
dump_histogram();
exit(0);
}