From f72751a73a6b6ad678d254335e031e4511282564 Mon Sep 17 00:00:00 2001 From: Veronika Molnarova Date: Thu, 3 Oct 2024 14:51:36 +0200 Subject: [PATCH] perf test: Restore sample rate for perf_event_attr Test "Setup struct perf_event_attr" consists of multiple test cases that can affect the max sample rate value for perf events. Some test cases check this value as it should not be lowered under the set minimum for the given test. Currently, it is possible for the test cases to affect each other as the previous tests can lower the sample rate, leading to a possible failure of some of the future test cases as the value is not restored at any point. # 10: Setup struct perf_event_attr: --- start --- test child forked, pid 104220 Using CPUID 0x00000000413fd0c1 running './tests/attr/test-record-C0' Current sample rate: 10000 running './tests/attr/test-record-basic' Current sample rate: 900 running './tests/attr/test-record-branch-any' Current sample rate: 600 running './tests/attr/test-record-dummy-C0' Current sample rate: 600 expected sample_period=4000, got 600 FAILED './tests/attr/test-record-dummy-C0' - match failure Restore the max sample rate value for perf events to a reasonable value before each test case if its value was lowered too much to ensure the same conditions for each test case. # 10: Setup struct perf_event_attr: --- start --- test child forked, pid 107222 Using CPUID 0x00000000413fd0c1 running './tests/attr/test-record-C0' Current sample rate: 10000 running './tests/attr/test-record-basic' Current sample rate: 800 running './tests/attr/test-record-branch-any' Current sample rate: 700 unsupp './tests/attr/test-record-branch-any' running './tests/attr/test-record-branch-filter-any' Current sample rate: 10000 running './tests/attr/test-record-count' Current sample rate: 10000 running './tests/attr/test-record-data' Current sample rate: 600 running './tests/attr/test-record-dummy-C0' Current sample rate: 800 running './tests/attr/test-record-freq' Current sample rate: 10000 ... Cc: Michael Petlan Cc: Radostin Stoyanov Signed-off-by: Veronika Molnarova Link: https://lore.kernel.org/r/20241003125136.15918-1-vmolnaro@redhat.com Signed-off-by: Namhyung Kim --- tools/perf/tests/attr.py | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/tools/perf/tests/attr.py b/tools/perf/tests/attr.py index e890c261ad26..3db9a7d78715 100644 --- a/tools/perf/tests/attr.py +++ b/tools/perf/tests/attr.py @@ -246,6 +246,23 @@ class Test(object): return False return True + def restore_sample_rate(self, value=10000): + try: + # Check value of sample_rate + with open("/proc/sys/kernel/perf_event_max_sample_rate", "r") as fIn: + curr_value = fIn.readline() + # If too low restore to reasonable value + if not curr_value or int(curr_value) < int(value): + with open("/proc/sys/kernel/perf_event_max_sample_rate", "w") as fOut: + fOut.write(str(value)) + + except IOError as e: + log.warning("couldn't restore sample_rate value: I/O error %s" % e) + except ValueError as e: + log.warning("couldn't restore sample_rate value: Value error %s" % e) + except TypeError as e: + log.warning("couldn't restore sample_rate value: Type error %s" % e) + def load_events(self, path, events): parser_event = configparser.ConfigParser() parser_event.read(path) @@ -283,6 +300,7 @@ class Test(object): if self.skip_test_kernel_until(): raise Notest(self, "new kernel skip") + self.restore_sample_rate() cmd = "PERF_TEST_ATTR=%s %s %s -o %s/perf.data %s" % (tempdir, self.perf, self.command, tempdir, self.args) ret = os.WEXITSTATUS(os.system(cmd)) -- 2.25.1