tools/perf/tests/keep-tracking.c

Source file repositories/reference/linux-study-clean/tools/perf/tests/keep-tracking.c

File Facts

System
Linux kernel
Corpus path
tools/perf/tests/keep-tracking.c
Extension
.c
Size
3735 bytes
Lines
165
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

while ((event = perf_mmap__read_event(&md->core)) != NULL) {
			if (event->header.type == PERF_RECORD_COMM &&
			    (pid_t)event->comm.pid == getpid() &&
			    (pid_t)event->comm.tid == getpid() &&
			    strcmp(event->comm.comm, comm) == 0)
				found += 1;
			perf_mmap__consume(&md->core);
		}
		perf_mmap__read_done(&md->core);
	}
	return found;
}

/**
 * test__keep_tracking - test using a dummy software event to keep tracking.
 *
 * This function implements a test that checks that tracking events continue
 * when an event is disabled but a dummy software event is not disabled.  If the
 * test passes %0 is returned, otherwise %-1 is returned.
 */
static int test__keep_tracking(struct test_suite *test __maybe_unused, int subtest __maybe_unused)
{
	struct record_opts opts = {
		.mmap_pages	     = UINT_MAX,
		.user_freq	     = UINT_MAX,
		.user_interval	     = ULLONG_MAX,
		.target		     = {
			.uses_mmap   = true,
		},
	};
	struct perf_thread_map *threads = NULL;
	struct perf_cpu_map *cpus = NULL;
	struct evlist *evlist = NULL;
	struct evsel *evsel = NULL;
	int found, err = -1;
	const char *comm;

	threads = thread_map__new_by_tid(getpid());
	CHECK_NOT_NULL__(threads);

	cpus = perf_cpu_map__new_online_cpus();
	CHECK_NOT_NULL__(cpus);

	evlist = evlist__new();
	CHECK_NOT_NULL__(evlist);

	perf_evlist__set_maps(&evlist->core, cpus, threads);

	CHECK__(parse_event(evlist, "dummy:u"));
	CHECK__(parse_event(evlist, "cpu-cycles:u"));

	evlist__config(evlist, &opts, NULL);

	evsel = evlist__first(evlist);

	evsel->core.attr.comm = 1;
	evsel->core.attr.disabled = 1;
	evsel->core.attr.enable_on_exec = 0;

	if (evlist__open(evlist) < 0) {
		pr_debug("Unable to open dummy and cycles event\n");
		err = TEST_SKIP;
		goto out_err;
	}

	CHECK__(evlist__mmap(evlist, UINT_MAX));

	/*
	 * First, test that a 'comm' event can be found when the event is
	 * enabled.
	 */

	evlist__enable(evlist);

	comm = "Test COMM 1";
	CHECK__(prctl(PR_SET_NAME, (unsigned long)comm, 0, 0, 0));

	evlist__disable(evlist);

	found = find_comm(evlist, comm);
	if (found != 1) {
		pr_debug("First time, failed to find tracking event.\n");
		goto out_err;
	}

	/*
	 * Secondly, test that a 'comm' event can be found when the event is
	 * disabled with the dummy event still enabled.
	 */

Annotation

Implementation Notes