[LTP] [PATCH v3] syscalls/nice05: Add testcase for nice() syscall

[Cyril Hrubis]

Hi!
> +static void verify_nice(void)
> +{
> +	intptr_t nice_inc_high = -1;
> +	intptr_t nice_inc_low = -2;
> +	char buf[4096] = {0};
> +	float sum_exec_runtime[2];
> +	pthread_t nice_low, nice_high;
> +	pid_t pid;
> +
> +	pid = SAFE_FORK();
> +	if (!pid) {
> +		TEST(pthread_barrier_init(&barrier, NULL, 3));
> +		if (TST_RET != 0) {
> +			tst_brk(TBROK | TTERRNO,
> +				"pthread_barrier_init() failed");
> +		}
> +
> +		SAFE_PTHREAD_CREATE(&nice_high, NULL, nice_high_thread,
> +			(void *)nice_inc_high);
> +		SAFE_PTHREAD_CREATE(&nice_low, NULL, nice_low_thread,
> +			(void *)nice_inc_low);
> +
> +		TEST(pthread_barrier_wait(&barrier));
> +		if (TST_RET != 0 && TST_RET != PTHREAD_BARRIER_SERIAL_THREAD) {
> +			tst_brk(TBROK | TTERRNO,
> +				"pthread_barrier_wait() failed");
> +		}
> +
> +		while (1)
> +			pause();
> +	}
> +
> +	sleep(tst_remaining_runtime());
> +	SAFE_KILL(pid, SIGSTOP);
> +
> +	sprintf(buf, "/proc/%d/sched", child_tid[0]);
> +	SAFE_FILE_SCANF(buf, "%*s %*s %*s %*s %*s"
> +			"%*s %*s %*f %*s %*s %*f %*s %*s %f",
> +			&sum_exec_runtime[0]);
> +
> +	sprintf(buf, "/proc/%d/sched", child_tid[1]);
> +	SAFE_FILE_SCANF(buf, "%*s %*s %*s %*s %*s"
> +			"%*s %*s %*f %*s %*s %*f %*s %*s %f",
> +			&sum_exec_runtime[1]);

The /proc/$PID/sched file is unfortunatelly only present if
CONFIG_SCHED_DEBUG was set in the kernel, which is not always the case,
and the test TBROKs on some of my testing targets.

Thinking of alternatives we can probably do clock_getcpuclockid() for
the threads and read the counters with clock_gettime().

-- 
Cyril Hrubis
chrubis@suse.cz