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); }