From ee74701ed8add8ad13e642e8618b51fd75add32d Mon Sep 17 00:00:00 2001 From: Wang Nan Date: Mon, 9 May 2016 01:47:51 +0000 Subject: [PATCH] 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: Wang Nan Tested-by: Arnaldo Carvalho de Melo Cc: Peter Zijlstra Cc: Zefan Li Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1462758471-89706-3-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/tests/Build | 1 + tools/perf/tests/backward-ring-buffer.c | 151 ++++++++++++++++++++++++ tools/perf/tests/builtin-test.c | 4 + tools/perf/tests/tests.h | 1 + 4 files changed, 157 insertions(+) create mode 100644 tools/perf/tests/backward-ring-buffer.c diff --git a/tools/perf/tests/Build b/tools/perf/tests/Build index 449fe97a555f..66a28982547b 100644 --- a/tools/perf/tests/Build +++ b/tools/perf/tests/Build @@ -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) diff --git a/tools/perf/tests/backward-ring-buffer.c b/tools/perf/tests/backward-ring-buffer.c new file mode 100644 index 000000000000..d9ba991a9a30 --- /dev/null +++ b/tools/perf/tests/backward-ring-buffer.c @@ -0,0 +1,151 @@ +/* + * Test backward bit in event attribute, read ring buffer from end to + * beginning + */ + +#include +#include +#include +#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; +} diff --git a/tools/perf/tests/builtin-test.c b/tools/perf/tests/builtin-test.c index 93c467015e71..0e95c20ecf6e 100644 --- a/tools/perf/tests/builtin-test.c +++ b/tools/perf/tests/builtin-test.c @@ -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, }, diff --git a/tools/perf/tests/tests.h b/tools/perf/tests/tests.h index 0fc946989cf0..c57e72c826d2 100644 --- a/tools/perf/tests/tests.h +++ b/tools/perf/tests/tests.h @@ -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 -- 2.20.1