[PATCH 3/5] perf cpumap: Add intersect function.

From: Ian Rogers <irogers@google.com>
To: Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Jiri Olsa <jolsa@kernel.org>, Namhyung Kim <namhyung@kernel.org>,
	Mathieu Poirier <mathieu.poirier@linaro.org>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Mike Leach <mike.leach@linaro.org>, Leo Yan <leo.yan@linaro.org>,
	John Garry <john.garry@huawei.com>, Will Deacon <will@kernel.org>,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>,
	Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>,
	Yonghong Song <yhs@fb.com>,
	John Fastabend <john.fastabend@gmail.com>,
	KP Singh <kpsingh@kernel.org>, Kajol Jain <kjain@linux.ibm.com>,
	James Clark <james.clark@arm.com>,
	German Gomez <german.gomez@arm.com>,
	Adrian Hunter <adrian.hunter@intel.com>,
	Riccardo Mancini <rickyman7@gmail.com>,
	Andi Kleen <ak@linux.intel.com>,
	Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com>,
	Alexander Antonov <alexander.antonov@linux.intel.com>,
	linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org,
	coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org,
	netdev@vger.kernel.org, bpf@vger.kernel.org
Cc: Stephane Eranian <eranian@google.com>, Ian Rogers <irogers@google.com>
Subject: [PATCH 3/5] perf cpumap: Add intersect function.
Date: Sun, 27 Mar 2022 23:24:12 -0700	[thread overview]
Message-ID: <20220328062414.1893550-4-irogers@google.com> (raw)
In-Reply-To: <20220328062414.1893550-1-irogers@google.com>

The merge function gives the union of two cpu maps. Add an intersect
function which will be used in the next change.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/lib/perf/cpumap.c              | 38 ++++++++++++++++++++++++++++
 tools/lib/perf/include/perf/cpumap.h |  2 ++
 2 files changed, 40 insertions(+)

diff --git a/tools/lib/perf/cpumap.c b/tools/lib/perf/cpumap.c
index 953bc50b0e41..56b4d213039f 100644
--- a/tools/lib/perf/cpumap.c
+++ b/tools/lib/perf/cpumap.c
@@ -393,3 +393,41 @@ struct perf_cpu_map *perf_cpu_map__merge(struct perf_cpu_map *orig,
 	perf_cpu_map__put(orig);
 	return merged;
 }
+
+struct perf_cpu_map *perf_cpu_map__intersect(struct perf_cpu_map *orig,
+					     struct perf_cpu_map *other)
+{
+	struct perf_cpu *tmp_cpus;
+	int tmp_len;
+	int i, j, k;
+	struct perf_cpu_map *merged = NULL;
+
+	if (perf_cpu_map__is_subset(other, orig))
+		return orig;
+	if (perf_cpu_map__is_subset(orig, other)) {
+		perf_cpu_map__put(orig);
+		return perf_cpu_map__get(other);
+	}
+
+	tmp_len = max(orig->nr, other->nr);
+	tmp_cpus = malloc(tmp_len * sizeof(struct perf_cpu));
+	if (!tmp_cpus)
+		return NULL;
+
+	i = j = k = 0;
+	while (i < orig->nr && j < other->nr) {
+		if (orig->map[i].cpu < other->map[j].cpu)
+			i++;
+		else if (orig->map[i].cpu > other->map[j].cpu)
+			j++;
+		else {
+			j++;
+			tmp_cpus[k++] = orig->map[i++];
+		}
+	}
+	if (k)
+		merged = cpu_map__trim_new(k, tmp_cpus);
+	free(tmp_cpus);
+	perf_cpu_map__put(orig);
+	return merged;
+}
diff --git a/tools/lib/perf/include/perf/cpumap.h b/tools/lib/perf/include/perf/cpumap.h
index 4a2edbdb5e2b..a2a7216c0b78 100644
--- a/tools/lib/perf/include/perf/cpumap.h
+++ b/tools/lib/perf/include/perf/cpumap.h
@@ -19,6 +19,8 @@ LIBPERF_API struct perf_cpu_map *perf_cpu_map__read(FILE *file);
 LIBPERF_API struct perf_cpu_map *perf_cpu_map__get(struct perf_cpu_map *map);
 LIBPERF_API struct perf_cpu_map *perf_cpu_map__merge(struct perf_cpu_map *orig,
 						     struct perf_cpu_map *other);
+LIBPERF_API struct perf_cpu_map *perf_cpu_map__intersect(struct perf_cpu_map *orig,
+							 struct perf_cpu_map *other);
 LIBPERF_API void perf_cpu_map__put(struct perf_cpu_map *map);
 LIBPERF_API struct perf_cpu perf_cpu_map__cpu(const struct perf_cpu_map *cpus, int idx);
 LIBPERF_API int perf_cpu_map__nr(const struct perf_cpu_map *cpus);
-- 
2.35.1.1021.g381101b075-goog

