Messages in this thread Patch in this message | | | Date | Tue, 29 Nov 2022 15:13:57 -0500 | Subject | Re: [PATCH v2 2/2] perf test: Add event group test | From | "Liang, Kan" <> |
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On 2022-11-29 6:19 a.m., Ravi Bangoria wrote: > Multiple events in a group can belong to one or more pmus, however > there are some limitations to it. One of the limitation is, perf > doesn't allow creating a group of events from different hw pmus. > Write a simple test to create various combinations of hw, sw and > uncore pmu events and verify group creation succeeds or fails as > expected. > > Signed-off-by: Ravi Bangoria <ravi.bangoria@amd.com> > --- > tools/perf/tests/Build | 1 + > tools/perf/tests/builtin-test.c | 1 + > tools/perf/tests/event_groups.c | 109 ++++++++++++++++++++++++++++++++ > tools/perf/tests/tests.h | 1 + > 4 files changed, 112 insertions(+) > create mode 100644 tools/perf/tests/event_groups.c > > diff --git a/tools/perf/tests/Build b/tools/perf/tests/Build > index 11b69023011b..658b5052c24d 100644 > --- a/tools/perf/tests/Build > +++ b/tools/perf/tests/Build > @@ -67,6 +67,7 @@ perf-y += expand-cgroup.o > perf-y += perf-time-to-tsc.o > perf-y += dlfilter-test.o > perf-y += sigtrap.o > +perf-y += event_groups.o > > $(OUTPUT)tests/llvm-src-base.c: tests/bpf-script-example.c tests/Build > $(call rule_mkdir) > diff --git a/tools/perf/tests/builtin-test.c b/tools/perf/tests/builtin-test.c > index 4c6ae59a4dfd..ddd8262bfa26 100644 > --- a/tools/perf/tests/builtin-test.c > +++ b/tools/perf/tests/builtin-test.c > @@ -110,6 +110,7 @@ static struct test_suite *generic_tests[] = { > &suite__perf_time_to_tsc, > &suite__dlfilter, > &suite__sigtrap, > + &suite__event_groups, > NULL, > }; > > diff --git a/tools/perf/tests/event_groups.c b/tools/perf/tests/event_groups.c > new file mode 100644 > index 000000000000..4002b467cc8f > --- /dev/null > +++ b/tools/perf/tests/event_groups.c > @@ -0,0 +1,109 @@ > +// SPDX-License-Identifier: GPL-2.0 > +#include <string.h> > +#include <unistd.h> > +#include <stdio.h> > +#include "linux/perf_event.h" > +#include "tests.h" > +#include "debug.h" > +#include "pmu.h" > +#include "pmus.h" > +#include "header.h" > +#include "../perf-sys.h" > + > +static int event_open(int type, unsigned long config, int group_fd) > +{ > + struct perf_event_attr attr; > + > + memset(&attr, 0, sizeof(struct perf_event_attr)); > + attr.type = type; > + attr.size = sizeof(struct perf_event_attr); > + attr.config = config; > + /* > + * When creating an event group, typically the group leader is > + * initialized with disabled set to 1 and any child events are > + * initialized with disabled set to 0. Despite disabled being 0, > + * the child events will not start until the group leader is > + * enabled. > + */ > + attr.disabled = group_fd == -1 ? 1 : 0; > + > + return sys_perf_event_open(&attr, -1, 0, group_fd, 0); > +} > + > +/* hw: cycles, sw: context-switch, uncore: [arch dependent] */ > +static int type[] = {0, 1, -1}; > +static unsigned long config[] = {0, 3, 0}; > + > +static int setup_uncore_event(void) > +{ > + struct perf_pmu *pmu; > + > + if (list_empty(&pmus)) > + perf_pmu__scan(NULL); > + > + perf_pmus__for_each_pmu(pmu) { > + if (pmu->is_uncore) {
Always using the first uncore PMU may trigger false alarm on some Intel platforms. For example, Intel has free running uncore PMUs (e.g., uncore_imc_free_running_0), which only supports special event encoding 0xff. The config 0 must fails. You may want to add the below check to ignore the free running uncore PMUs. if (strstr(pmu->name, "free_running")) continue;
Also, some uncore PMUs only support two counters. But the test assumes that the number of counters > 2. You may want to limit the size of the group for 2 for a pure uncore group.
Thanks, Kan
> + pr_debug("Using %s for uncore pmu event\n", pmu->name); > + type[2] = pmu->type; > + return 0; > + } > + } > + return -1; > +} > + > +static int run_test(int i, int j, int k) > +{ > + int erroneous = ((((1 << i) | (1 << j) | (1 << k)) & 5) == 5); > + int group_fd, sibling_fd1, sibling_fd2; > + > + group_fd = event_open(type[i], config[i], -1); > + if (group_fd == -1) > + return -1; > + > + sibling_fd1 = event_open(type[j], config[j], group_fd); > + if (sibling_fd1 == -1) { > + close(group_fd); > + return erroneous ? 0 : -1; > + } > + > + sibling_fd2 = event_open(type[k], config[k], group_fd); > + if (sibling_fd2 == -1) { > + close(sibling_fd1); > + close(group_fd); > + return erroneous ? 0 : -1; > + } > + > + close(sibling_fd2); > + close(sibling_fd1); > + close(group_fd); > + return erroneous ? -1 : 0; > +} > + > +static int test__event_groups(struct test_suite *text __maybe_unused, int subtest __maybe_unused) > +{ > + int i, j, k; > + int ret; > + int r; > + > + ret = setup_uncore_event(); > + if (ret || type[2] == -1) > + return TEST_SKIP; > + > + ret = TEST_OK; > + for (i = 0; i < 3; i++) { > + for (j = 0; j < 3; j++) { > + for (k = 0; k < 3; k++) { > + r = run_test(i, j, k); > + if (r) > + ret = TEST_FAIL; > + > + pr_debug("0x%x 0x%lx, 0x%x 0x%lx, 0x%x 0x%lx: %s\n", > + type[i], config[i], type[j], config[j], > + type[k], config[k], r ? "Fail" : "Pass"); > + } > + } > + } > + return ret; > +} > + > +DEFINE_SUITE("Event groups", event_groups); > diff --git a/tools/perf/tests/tests.h b/tools/perf/tests/tests.h > index e15f24cfc909..fb4b5ad4dd0f 100644 > --- a/tools/perf/tests/tests.h > +++ b/tools/perf/tests/tests.h > @@ -147,6 +147,7 @@ DECLARE_SUITE(expand_cgroup_events); > DECLARE_SUITE(perf_time_to_tsc); > DECLARE_SUITE(dlfilter); > DECLARE_SUITE(sigtrap); > +DECLARE_SUITE(event_groups); > > /* > * PowerPC and S390 do not support creation of instruction breakpoints using the
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