Commit ee74701e authored by Wang Nan's avatar Wang Nan Committed by Arnaldo Carvalho de Melo
Browse files

perf tests: Add test to check backward ring buffer 



This test checks reading from backward ring buffer.

Test result:

  # ~/perf test 'ring buffer'
  45: Test backward reading from ring buffer                   : Ok

The test case is a while loop which calls prctl(PR_SET_NAME) multiple
times.  Each prctl should issue 2 events: one PERF_RECORD_SAMPLE, one
PERF_RECORD_COMM.

The first round creates a relative large ring buffer (256 pages). It can
afford all events. Read from it and check the count of each type of
events.

The second round creates a small ring buffer (1 page) and makes it
overwritable. Check the correctness of the buffer.

Signed-off-by: default avatarWang Nan <wangnan0@huawei.com>
Tested-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1462758471-89706-3-git-send-email-wangnan0@huawei.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent e24c7520

tools/perf/tests/Build

+1 −0
Original line number Diff line number Diff line
@@ -38,6 +38,7 @@ perf-y += cpumap.o 
perf-y += stat.o

perf-y += event_update.o

perf-y += event-times.o

perf-y += backward-ring-buffer.o



$(OUTPUT)tests/llvm-src-base.c: tests/bpf-script-example.c tests/Build

	$(call rule_mkdir)

tools/perf/tests/backward-ring-buffer.c

0 → 100644
+151 −0
Original line number Diff line number Diff line 
/*

 * Test backward bit in event attribute, read ring buffer from end to

 * beginning

 */



#include <perf.h>

#include <evlist.h>

#include <sys/prctl.h>

#include "tests.h"

#include "debug.h"



#define NR_ITERS 111



static void testcase(void)

{

	int i;



	for (i = 0; i < NR_ITERS; i++) {

		char proc_name[10];



		snprintf(proc_name, sizeof(proc_name), "p:%d\n", i);

		prctl(PR_SET_NAME, proc_name);

	}

}



static int count_samples(struct perf_evlist *evlist, int *sample_count,

			 int *comm_count)

{

	int i;



	for (i = 0; i < evlist->nr_mmaps; i++) {

		union perf_event *event;



		perf_evlist__mmap_read_catchup(evlist, i);

		while ((event = perf_evlist__mmap_read_backward(evlist, i)) != NULL) {

			const u32 type = event->header.type;



			switch (type) {

			case PERF_RECORD_SAMPLE:

				(*sample_count)++;

				break;

			case PERF_RECORD_COMM:

				(*comm_count)++;

				break;

			default:

				pr_err("Unexpected record of type %d\n", type);

				return TEST_FAIL;

			}

		}

	}

	return TEST_OK;

}



static int do_test(struct perf_evlist *evlist, int mmap_pages,

		   int *sample_count, int *comm_count)

{

	int err;

	char sbuf[STRERR_BUFSIZE];



	err = perf_evlist__mmap(evlist, mmap_pages, true);

	if (err < 0) {

		pr_debug("perf_evlist__mmap: %s\n",

			 strerror_r(errno, sbuf, sizeof(sbuf)));

		return TEST_FAIL;

	}



	perf_evlist__enable(evlist);

	testcase();

	perf_evlist__disable(evlist);



	err = count_samples(evlist, sample_count, comm_count);

	perf_evlist__munmap(evlist);

	return err;

}





int test__backward_ring_buffer(int subtest __maybe_unused)

{

	int ret = TEST_SKIP, err, sample_count = 0, comm_count = 0;

	char pid[16], sbuf[STRERR_BUFSIZE];

	struct perf_evlist *evlist;

	struct perf_evsel *evsel __maybe_unused;

	struct parse_events_error parse_error;

	struct record_opts opts = {

		.target = {

			.uid = UINT_MAX,

			.uses_mmap = true,

		},

		.freq	      = 0,

		.mmap_pages   = 256,

		.default_interval = 1,

	};



	snprintf(pid, sizeof(pid), "%d", getpid());

	pid[sizeof(pid) - 1] = '\0';

	opts.target.tid = opts.target.pid = pid;



	evlist = perf_evlist__new();

	if (!evlist) {

		pr_debug("No ehough memory to create evlist\n");

		return TEST_FAIL;

	}



	err = perf_evlist__create_maps(evlist, &opts.target);

	if (err < 0) {

		pr_debug("Not enough memory to create thread/cpu maps\n");

		goto out_delete_evlist;

	}



	bzero(&parse_error, sizeof(parse_error));

	err = parse_events(evlist, "syscalls:sys_enter_prctl", &parse_error);

	if (err) {

		pr_debug("Failed to parse tracepoint event, try use root\n");

		ret = TEST_SKIP;

		goto out_delete_evlist;

	}



	perf_evlist__config(evlist, &opts, NULL);



	/* Set backward bit, ring buffer should be writing from end */

	evlist__for_each(evlist, evsel)

		evsel->attr.write_backward = 1;



	err = perf_evlist__open(evlist);

	if (err < 0) {

		pr_debug("perf_evlist__open: %s\n",

			 strerror_r(errno, sbuf, sizeof(sbuf)));

		goto out_delete_evlist;

	}



	ret = TEST_FAIL;

	err = do_test(evlist, opts.mmap_pages, &sample_count,

		      &comm_count);

	if (err != TEST_OK)

		goto out_delete_evlist;



	if ((sample_count != NR_ITERS) || (comm_count != NR_ITERS)) {

		pr_err("Unexpected counter: sample_count=%d, comm_count=%d\n",

		       sample_count, comm_count);

		goto out_delete_evlist;

	}



	err = do_test(evlist, 1, &sample_count, &comm_count);

	if (err != TEST_OK)

		goto out_delete_evlist;



	ret = TEST_OK;

out_delete_evlist:

	perf_evlist__delete(evlist);

	return ret;

}

tools/perf/tests/builtin-test.c

+4 −0
Original line number Diff line number Diff line
@@ -207,6 +207,10 @@ static struct test generic_tests[] = { 
		.desc = "Test events times",

		.func = test__event_times,

	},

	{

		.desc = "Test backward reading from ring buffer",

		.func = test__backward_ring_buffer,

	},

	{

		.func = NULL,

	},

tools/perf/tests/tests.h

+1 −0
Original line number Diff line number Diff line
@@ -86,6 +86,7 @@ int test__synthesize_stat(int subtest); 
int test__synthesize_stat_round(int subtest);

int test__event_update(int subtest);

int test__event_times(int subtest);

int test__backward_ring_buffer(int subtest);



#if defined(__arm__) || defined(__aarch64__)

#ifdef HAVE_DWARF_UNWIND_SUPPORT

CRA Git | Maintained and supported by SUSTech CRA and CCSE