int main(int argc, char *argv[]) {
DBusError error;
DBusConnection *bus;
int r, max_realtime_priority, min_nice_level;
long long rttime_nsec_max;
struct rlimit rlim;
dbus_error_init(&error);
if (!(bus = dbus_bus_get(DBUS_BUS_SYSTEM, &error))) {
fprintf(stderr, "Failed to connect to system bus: %s\n", error.message);
return 1;
}
if ((max_realtime_priority = rtkit_get_max_realtime_priority(bus)) < 0)
fprintf(stderr, "Failed to retrieve max realtime priority: %s\n", strerror(-max_realtime_priority));
else
printf("Max realtime priority is: %d\n", max_realtime_priority);
if ((r = rtkit_get_min_nice_level(bus, &min_nice_level)))
fprintf(stderr, "Failed to retrieve min nice level: %s\n", strerror(-r));
else
printf("Min nice level is: %d\n", min_nice_level);
if ((rttime_nsec_max = rtkit_get_rttime_nsec_max(bus)) < 0)
fprintf(stderr, "Failed to retrieve rttime limit: %s\n", strerror(-rttime_nsec_max));
else
printf("Rttime limit is: %lld ns\n", rttime_nsec_max);
memset(&rlim, 0, sizeof(rlim));
rlim.rlim_cur = rlim.rlim_max = 100000000ULL; /* 100ms */
if ((setrlimit(RLIMIT_RTTIME, &rlim) < 0))
fprintf(stderr, "Failed to set RLIMIT_RTTIME: %s\n", strerror(errno));
print_status("before");
if ((r = rtkit_make_high_priority(bus, 0, -10)) < 0)
fprintf(stderr, "Failed to become high priority: %s\n", strerror(-r));
else
printf("Successfully became high priority.\n");
print_status("after high priority");
if ((r = rtkit_make_realtime(bus, 0, 10)) < 0)
fprintf(stderr, "Failed to become realtime: %s\n", strerror(-r));
else
printf("Successfully became realtime.\n");
print_status("after realtime");
dbus_connection_unref(bus);
return 0;
}
int fluid_rtkit_make_realtime(pid_t thread, int priority) {
DBusConnection *conn = NULL;
DBusError error;
int max_prio, res;
long long max_rttime;
struct rlimit old_limit, new_limit;
if (!dbus_threads_init_default())
return -ENOMEM;
/* Initialize system bus connection */
dbus_error_init(&error);
conn = dbus_bus_get_private(DBUS_BUS_SYSTEM, &error);
if (conn == NULL) {
res = translate_error(error.name);
dbus_error_free(&error);
return res;
}
dbus_error_free(&error);
/* Make sure we don't fail by wanting too much */
max_prio = rtkit_get_max_realtime_priority(conn);
if (max_prio < 0)
MAKE_REALTIME_RETURN(max_prio);
if (priority >= max_prio)
priority = max_prio;
/* Enforce RLIMIT_RTTIME, also a must for obtaining rt prio through rtkit */
max_rttime = rtkit_get_rttime_nsec_max(conn);
if (max_rttime < 0)
MAKE_REALTIME_RETURN(max_rttime);
new_limit.rlim_cur = new_limit.rlim_max = max_rttime;
if (getrlimit(RLIMIT_RTTIME, &old_limit) < 0)
MAKE_REALTIME_RETURN(-1);
if (setrlimit(RLIMIT_RTTIME, &new_limit) < 0)
MAKE_REALTIME_RETURN(-1);
/* Finally, let's try */
res = rtkit_make_realtime(conn, thread, priority);
if (res != 0) {
setrlimit(RLIMIT_RTTIME, &old_limit);
}
MAKE_REALTIME_RETURN(res);
}
