tools/testing/selftests/powerpc/math/vsx_preempt.c

Source file repositories/reference/linux-study-clean/tools/testing/selftests/powerpc/math/vsx_preempt.c

File Facts

System
Linux kernel
Corpus path
tools/testing/selftests/powerpc/math/vsx_preempt.c
Extension
.c
Size
3559 bytes
Lines
146
Domain
Support Tooling And Documentation
Bucket
tools
Inferred role
Support Tooling And Documentation: implementation source
Status
source implementation candidate

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

long vsx_memcmp(vector int *a) {
	vector int zero = {0, 0, 0, 0};
	int i;

	FAIL_IF(a != varray);

	for(i = 0; i < 12; i++) {
		if (memcmp(&a[i + 12], &zero, sizeof(vector int)) == 0) {
			fprintf(stderr, "Detected zero from the VSX reg %d\n", i + 12);
			return 2;
		}
	}

	if (memcmp(a, &a[12], 12 * sizeof(vector int))) {
		long *p = (long *)a;
		fprintf(stderr, "VSX mismatch\n");
		for (i = 0; i < 24; i=i+2)
			fprintf(stderr, "%d: 0x%08lx%08lx | 0x%08lx%08lx\n",
					i/2 + i%2 + 20, p[i], p[i + 1], p[i + 24], p[i + 25]);
		return 1;
	}
	return 0;
}

void *preempt_vsx_c(void *p)
{
	int i, j;
	long rc;
	srand(pthread_self());
	for (i = 0; i < 12; i++)
		for (j = 0; j < 4; j++) {
			varray[i][j] = rand();
			/* Don't want zero because it hides kernel problems */
			if (varray[i][j] == 0)
				j--;
		}
	rc = preempt_vsx(varray, &threads_starting, &running);
	if (rc == 2)
		fprintf(stderr, "Caught zeros in VSX compares\n");
	return (void *)rc;
}

int test_preempt_vsx(void)
{
	int i, rc, threads;
	pthread_t *tids;

	SKIP_IF(!have_hwcap(PPC_FEATURE_HAS_VSX));

	threads = sysconf(_SC_NPROCESSORS_ONLN) * THREAD_FACTOR;
	tids = malloc(threads * sizeof(pthread_t));
	FAIL_IF(!tids);

	running = true;
	threads_starting = threads;
	for (i = 0; i < threads; i++) {
		rc = pthread_create(&tids[i], NULL, preempt_vsx_c, NULL);
		FAIL_IF(rc);
	}

	setbuf(stdout, NULL);
	/* Not really nessesary but nice to wait for every thread to start */
	printf("\tWaiting for %d workers to start...", threads_starting);
	while(threads_starting)
		asm volatile("": : :"memory");
	printf("done\n");

	printf("\tWaiting for %d seconds to let some workers get preempted...", PREEMPT_TIME);
	sleep(PREEMPT_TIME);
	printf("done\n");

	printf("\tStopping workers...");
	/*
	 * Working are checking this value every loop. In preempt_vsx 'cmpwi r5,0; bne 2b'.
	 * r5 will have loaded the value of running.
	 */
	running = 0;
	for (i = 0; i < threads; i++) {
		void *rc_p;
		pthread_join(tids[i], &rc_p);

		/*
		 * Harness will say the fail was here, look at why preempt_vsx
		 * returned
		 */
		if ((long) rc_p)
			printf("oops\n");
		FAIL_IF((long) rc_p);
	}
	printf("done\n");

Annotation

Implementation Notes