Hello, Working on a real time application, Getting runtime error at sched_setattr as "Operation Not permitted".Running on Ubuntu 16.04 LTS (4.4.0-97-generic kernel, x86_64 platform) C program code excerpt as below: unsigned int flags = 0; sched_getattr(0, &attr, sizeof (struct sched_attr), 0); if (ret != 0) perror("getattr failed:"); attr.sched_policy = SCHED_DEADLINE; attr.sched_runtime = 5 * 100 * 1000; attr.sched_deadline = 8 * 100 * 1000; attr.sched_period = 10 * 100 * 1000; attr.size = sizeof (attr); attr.sched_flags = 0; attr.sched_nice = 0; attr.sched_priority = 0; if(sched_setaffinity(0,sizeof(set), &set) < 0) { perror("sched_setaffinity :"); return 0; } ret = sched_setattr(0, &attr, flags); if(ret!=0) { perror("sched_setattr failed: "); } But, If I comment the sched_setaffinity() call, it runs without error. Also, using SCHED_FIFO by calling sched_setscheduler() doesn't give me any error after setting CPU affinity. Only the combination of sched_setaffinity with sched_setattr() generates error. I am running in sudo mode. Thanks in advance, Bhargav -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html