perf tools: Add optional support for libpfm4

This patch links perf with the libpfm4 library if it is available and
LIBPFM4 is passed to the build. The libpfm4 library contains hardware
event tables for all processors supported by perf_events. It is a helper
library that helps convert from a symbolic event name to the event
encoding required by the underlying kernel interface. This library is
open-source and available from: http://perfmon2.sf.net.

With this patch, it is possible to specify full hardware events by name.
Hardware filters are also supported. Events must be specified via the
--pfm-events and not -e option. Both options are active at the same time
and it is possible to mix and match:

  $ perf stat --pfm-events inst_retired:any_p:c=1:i -e cycles ....

One needs to explicitely ask for its inclusion by using the LIBPFM4 make
command line option, ie its opt-in rather than opt-out of feature
detection and build support.

Signed-off-by: Stephane Eranian <eranian@google.com>
Reviewed-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andrii Nakryiko <andriin@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Igor Lubashev <ilubashe@akamai.com>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Jiwei Sun <jiwei.sun@windriver.com>
Cc: John Garry <john.garry@huawei.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yonghong Song <yhs@fb.com>
Cc: bpf@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: yuzhoujian <yuzhoujian@didichuxing.com>
Link: http://lore.kernel.org/lkml/20200505182943.218248-2-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

4 files changed, 216 insertions, 0 deletions

diff --git a/tools/perf/tests/Build b/tools/perf/tests/Build
index 446fe14c24cf..cd00498a5dce 100644
--- a/tools/perf/tests/Build
+++ b/tools/perf/tests/Build
@@ -58,6 +58,7 @@ perf-y += time-utils-test.o
 perf-y += genelf.o
 perf-y += api-io.o
 perf-y += demangle-java-test.o
+perf-y += pfm.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 f1dc2fe93dd8..da5b6cc23f25 100644
--- a/tools/perf/tests/builtin-test.c
+++ b/tools/perf/tests/builtin-test.c
@@ -317,6 +317,15 @@ static struct test generic_tests[] = {
 		.func = test__jit_write_elf,
 	},
 	{
+		.desc = "Test libpfm4 support",
+		.func = test__pfm,
+		.subtest = {
+			.skip_if_fail	= true,
+			.get_nr		= test__pfm_subtest_get_nr,
+			.get_desc	= test__pfm_subtest_get_desc,
+		}
+	},
+	{
 		.desc = "Test api io",
 		.func = test__api_io,
 	},
diff --git a/tools/perf/tests/pfm.c b/tools/perf/tests/pfm.c
new file mode 100644
index 000000000000..76a53126efdf
--- /dev/null
+++ b/tools/perf/tests/pfm.c
@@ -0,0 +1,203 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Test support for libpfm4 event encodings.
+ *
+ * Copyright 2020 Google LLC.
+ */
+#include "tests.h"
+#include "util/debug.h"
+#include "util/evlist.h"
+#include "util/pfm.h"
+
+#include <linux/kernel.h>
+
+#ifdef HAVE_LIBPFM
+static int test__pfm_events(void);
+static int test__pfm_group(void);
+#endif
+
+static const struct {
+	int (*func)(void);
+	const char *desc;
+} pfm_testcase_table[] = {
+#ifdef HAVE_LIBPFM
+	{
+		.func = test__pfm_events,
+		.desc = "test of individual --pfm-events",
+	},
+	{
+		.func = test__pfm_group,
+		.desc = "test groups of --pfm-events",
+	},
+#endif
+};
+
+#ifdef HAVE_LIBPFM
+static int count_pfm_events(struct perf_evlist *evlist)
+{
+	struct perf_evsel *evsel;
+	int count = 0;
+
+	perf_evlist__for_each_entry(evlist, evsel) {
+		count++;
+	}
+	return count;
+}
+
+static int test__pfm_events(void)
+{
+	struct evlist *evlist;
+	struct option opt;
+	size_t i;
+	const struct {
+		const char *events;
+		int nr_events;
+	} table[] = {
+		{
+			.events = "",
+			.nr_events = 0,
+		},
+		{
+			.events = "instructions",
+			.nr_events = 1,
+		},
+		{
+			.events = "instructions,cycles",
+			.nr_events = 2,
+		},
+		{
+			.events = "stereolab",
+			.nr_events = 0,
+		},
+		{
+			.events = "instructions,instructions",
+			.nr_events = 2,
+		},
+		{
+			.events = "stereolab,instructions",
+			.nr_events = 0,
+		},
+		{
+			.events = "instructions,stereolab",
+			.nr_events = 1,
+		},
+	};
+
+	for (i = 0; i < ARRAY_SIZE(table); i++) {
+		evlist = evlist__new();
+		if (evlist == NULL)
+			return -ENOMEM;
+
+		opt.value = evlist;
+		parse_libpfm_events_option(&opt,
+					table[i].events,
+					0);
+		TEST_ASSERT_EQUAL(table[i].events,
+				count_pfm_events(&evlist->core),
+				table[i].nr_events);
+		TEST_ASSERT_EQUAL(table[i].events,
+				evlist->nr_groups,
+				0);
+
+		evlist__delete(evlist);
+	}
+	return 0;
+}
+
+static int test__pfm_group(void)
+{
+	struct evlist *evlist;
+	struct option opt;
+	size_t i;
+	const struct {
+		const char *events;
+		int nr_events;
+		int nr_groups;
+	} table[] = {
+		{
+			.events = "{},",
+			.nr_events = 0,
+			.nr_groups = 0,
+		},
+		{
+			.events = "{instructions}",
+			.nr_events = 1,
+			.nr_groups = 1,
+		},
+		{
+			.events = "{instructions},{}",
+			.nr_events = 1,
+			.nr_groups = 1,
+		},
+		{
+			.events = "{},{instructions}",
+			.nr_events = 0,
+			.nr_groups = 0,
+		},
+		{
+			.events = "{instructions},{instructions}",
+			.nr_events = 2,
+			.nr_groups = 2,
+		},
+		{
+			.events = "{instructions,cycles},{instructions,cycles}",
+			.nr_events = 4,
+			.nr_groups = 2,
+		},
+		{
+			.events = "{stereolab}",
+			.nr_events = 0,
+			.nr_groups = 0,
+		},
+		{
+			.events =
+			"{instructions,cycles},{instructions,stereolab}",
+			.nr_events = 3,
+			.nr_groups = 1,
+		},
+	};
+
+	for (i = 0; i < ARRAY_SIZE(table); i++) {
+		evlist = evlist__new();
+		if (evlist == NULL)
+			return -ENOMEM;
+
+		opt.value = evlist;
+		parse_libpfm_events_option(&opt,
+					table[i].events,
+					0);
+		TEST_ASSERT_EQUAL(table[i].events,
+				count_pfm_events(&evlist->core),
+				table[i].nr_events);
+		TEST_ASSERT_EQUAL(table[i].events,
+				evlist->nr_groups,
+				table[i].nr_groups);
+
+		evlist__delete(evlist);
+	}
+	return 0;
+}
+#endif
+
+const char *test__pfm_subtest_get_desc(int i)
+{
+	if (i < 0 || i >= (int)ARRAY_SIZE(pfm_testcase_table))
+		return NULL;
+	return pfm_testcase_table[i].desc;
+}
+
+int test__pfm_subtest_get_nr(void)
+{
+	return (int)ARRAY_SIZE(pfm_testcase_table);
+}
+
+int test__pfm(struct test *test __maybe_unused, int i __maybe_unused)
+{
+#ifdef HAVE_LIBPFM
+	if (i < 0 || i >= (int)ARRAY_SIZE(pfm_testcase_table))
+		return TEST_FAIL;
+	return pfm_testcase_table[i].func();
+#else
+	return TEST_SKIP;
+#endif
+}
diff --git a/tools/perf/tests/tests.h b/tools/perf/tests/tests.h
index 12856bc6f411..76a4e352eaaf 100644
--- a/tools/perf/tests/tests.h
+++ b/tools/perf/tests/tests.h
@@ -118,6 +118,9 @@ int test__time_utils(struct test *t, int subtest);
 int test__jit_write_elf(struct test *test, int subtest);
 int test__api_io(struct test *test, int subtest);
 int test__demangle_java(struct test *test, int subtest);
+int test__pfm(struct test *test, int subtest);
+const char *test__pfm_subtest_get_desc(int subtest);
+int test__pfm_subtest_get_nr(void);
 
 bool test__bp_signal_is_supported(void);
 bool test__bp_account_is_supported(void);