Re: [LTP] [PATCH v1] Rewrite msgstress testing suite

[Cyril Hrubis <chrubis@suse.cz>]

Hi!
First of all this patch removes all users of the libltpipc library but
keeps the library orphaned in libs/ leaving a dead code.

Secondly if you look at the libmsgctl.c you can actually see that the
reader and writer pair sends messages in a loop. This is imporatant
because without that the test can be hardly called a stress test. The
point is to start as much processes as possible that keep sending
messages around so that eventually we saturate the system. The new test
just sends a single message, which means that the children finish too
quickly and we never run more than a single digit of read/write pairs.
Given that we now have a runtime support in the test library we should
change this so that the reader/write paris continue to send messages
around until we are out of runtime. And the runtime should be at least a
minute.

> +static void reader(const int id)
> +{
> +	int size;
> +	struct sysv_msg msg_recv;
> +	struct sysv_data *buff = NULL;
>  
> -	/* Fork a number of processes, each of which will
> -	 * create a message queue with one reader/writer
> -	 * pair which will read and write a number (iterations)
> -	 * of random length messages with specific values.
> -	 */
> +	memset(&msg_recv, 0, sizeof(struct sysv_msg));
>  
> -	for (i = 0; i < nprocs; i++) {
> -		fflush(stdout);
> -		if ((pid = FORK_OR_VFORK()) < 0) {
> -			tst_brkm(TFAIL,
> -				 NULL,
> -				 "\tFork failed (may be OK if under stress)");
> -		}
> -		/* Child does this */
> -		if (pid == 0) {
> -			procstat = 1;
> -			exit(dotest(keyarray[i], i));
> +	size = SAFE_MSGRCV(id, &msg_recv, 100, MSGTYPE, 0);
> +
> +	for (int i = 0; i < ipc_data_len; i++) {
> +		if (ipc_data[i].id == id) {
> +			buff = ipc_data + i;
> +			break;
>  		}
> -		pidarray[i] = pid;
>  	}
>  
> -	count = 0;
> -	while (1) {
> -		if ((wait(&status)) > 0) {
> -			if (status >> 8 != 0) {
> -				tst_brkm(TFAIL, NULL,
> -					 "Child exit status = %d",
> -					 status >> 8);
> -			}
> -			count++;
> -		} else {
> -			if (errno != EINTR) {
> -				break;
> -			}
> -#ifdef DEBUG
> -			tst_resm(TINFO, "Signal detected during wait");
> -#endif
> -		}
> +	if (!buff) {
> +		tst_brk(TBROK, "Can't find original message. This is a test issue!");
> +		return;
>  	}
> -	/* Make sure proper number of children exited */
> -	if (count != nprocs) {
> -		tst_brkm(TFAIL,
> -			 NULL,
> -			 "Wrong number of children exited, Saw %d, Expected %d",
> -			 count, nprocs);
> +
> +	TST_EXP_EQ_LI(msg_recv.type, buff->msg.type);
> +	TST_EXP_EQ_LI(msg_recv.data.len, buff->msg.data.len);
> +
> +	for (int i = 0; i < size; i++) {
> +		if (msg_recv.data.pbytes[i] != buff->msg.data.pbytes[i]) {
> +			tst_res(TFAIL, "Received wrong data at index %d: %x != %x", i,
> +				msg_recv.data.pbytes[i],
> +				buff->msg.data.pbytes[i]);
> +
> +			goto exit;
> +		}
>  	}
>  
> -	tst_resm(TPASS, "Test ran successfully!");
> +	tst_res(TPASS, "Received correct data");

This spams the test output with a few hundreds of lines of output, which
is known to choke test runners. For this case we should probably output
one single TPASS at the end of the test.

Also this seems to be a common pattern, so we may as well add a function
into the test library that would produce TPASS unless we have seen a
FAIL/BROK/WARN. Or maybe just a function that would return sum of the
result counters so that we can do:

	if (tst_get_res(TFAIL|TBROK|TWARN))
		tst_res(TPASS, "All data were received correctly");


-- 
Cyril Hrubis
chrubis@suse.cz

-- 
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