[PATCH v4 3/4] perf record: apply affinity masks when reading mmap buffers

[Alexey Budankov]

Build node cpu masks for mmap data buffers. Apply node cpu
masks to tool thread every time it references data buffers
cross node or cross cpu.

Signed-off-by: Alexey Budankov <alexey.budankov@xxxxxxxxxxxxxxx>
---
Changes in v4:
- corrected mmap_params->cpu_map initialization to be based on /sys/devices/system/cpu/online
- separated node cpu map generation into build_node_mask()
Changes in v3:
- separated mask manipulations into __adjust_affinity() and __setup_affinity_mask()
- implemented mapping of c index into online cpu index
Changes in v2:
- separated AIO buffers binding to patch 2/4
---
 tools/perf/builtin-record.c | 14 ++++++++++++++
 tools/perf/util/evlist.c    |  6 +++++-
 tools/perf/util/mmap.c      | 23 ++++++++++++++++++++++-
 tools/perf/util/mmap.h      |  1 +
 4 files changed, 42 insertions(+), 2 deletions(-)

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index e5a108b11d46..553c2fabf3c1 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -536,6 +536,9 @@ static int record__mmap_evlist(struct record *rec,
 	struct record_opts *opts = &rec->opts;
 	char msg[512];
 
+	if (opts->affinity != PERF_AFFINITY_SYS)
+		cpu__setup_cpunode_map();
+
 	if (perf_evlist__mmap_ex(evlist, opts->mmap_pages,
 				 opts->auxtrace_mmap_pages,
 				 opts->auxtrace_snapshot_mode,
@@ -728,6 +731,16 @@ static struct perf_event_header finished_round_event = {
 	.type = PERF_RECORD_FINISHED_ROUND,
 };
 
+static void record__adjust_affinity(struct record *rec, struct perf_mmap *map)
+{
+	if (rec->opts.affinity != PERF_AFFINITY_SYS &&
+	    !CPU_EQUAL(&rec->affinity_mask, &map->affinity_mask)) {
+		CPU_ZERO(&rec->affinity_mask);
+		CPU_OR(&rec->affinity_mask, &rec->affinity_mask, &map->affinity_mask);
+		sched_setaffinity(0, sizeof(rec->affinity_mask), &rec->affinity_mask);
+	}
+}
+
 static int record__mmap_read_evlist(struct record *rec, struct perf_evlist *evlist,
 				    bool overwrite)
 {
@@ -755,6 +768,7 @@ static int record__mmap_read_evlist(struct record *rec, struct perf_evlist *evli
 		struct perf_mmap *map = &maps[i];
 
 		if (map->base) {
+			record__adjust_affinity(rec, map);
 			if (!record__aio_enabled(rec)) {
 				if (perf_mmap__push(map, rec, record__pushfn) != 0) {
 					rc = -1;
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 08cedb643ea6..178d3280ba62 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -1032,7 +1032,11 @@ int perf_evlist__mmap_ex(struct perf_evlist *evlist, unsigned int pages,
 	 * Its value is decided by evsel's write_backward.
 	 * So &mp should not be passed through const pointer.
 	 */
-	struct mmap_params mp = { .nr_cblocks = nr_cblocks, .affinity = affinity };
+	struct mmap_params mp = {
+		.nr_cblocks	= nr_cblocks,
+		.affinity	= affinity,
+		.cpu_map	= cpu_map__new(NULL) /* from /sys/devices/system/cpu/online */
+	};
 
 	if (!evlist->mmap)
 		evlist->mmap = perf_evlist__alloc_mmap(evlist, false);
diff --git a/tools/perf/util/mmap.c b/tools/perf/util/mmap.c
index 34be9f900575..8ff2f1c243a2 100644
--- a/tools/perf/util/mmap.c
+++ b/tools/perf/util/mmap.c
@@ -383,6 +383,27 @@ void perf_mmap__munmap(struct perf_mmap *map)
 	auxtrace_mmap__munmap(&map->auxtrace_mmap);
 }
 
+static void build_node_mask(const struct cpu_map *cpu_map, int node, cpu_set_t *mask)
+{
+	int c, cpu, nr_cpus;
+
+	nr_cpus = cpu_map__nr(cpu_map);
+	for (c = 0; c < nr_cpus; c++) {
+		cpu = cpu_map->map[c]; /* map c index to online cpu index */
+		if (cpu__get_node(cpu) == node)
+			CPU_SET(cpu, mask);
+	}
+}
+
+static void perf_mmap__setup_affinity_mask(struct perf_mmap *map, struct mmap_params *mp)
+{
+	CPU_ZERO(&map->affinity_mask);
+	if (mp->affinity == PERF_AFFINITY_NODE && cpu__max_node() > 1 && mp->cpu_map)
+		build_node_mask(mp->cpu_map, cpu__get_node(map->cpu), &map->affinity_mask);
+	else if (mp->affinity == PERF_AFFINITY_CPU)
+		CPU_SET(map->cpu, &map->affinity_mask);
+}
+
 int perf_mmap__mmap(struct perf_mmap *map, struct mmap_params *mp, int fd, int cpu)
 {
 	/*
@@ -412,7 +433,7 @@ int perf_mmap__mmap(struct perf_mmap *map, struct mmap_params *mp, int fd, int c
 	map->fd = fd;
 	map->cpu = cpu;
 
-	CPU_ZERO(&map->affinity_mask);
+	perf_mmap__setup_affinity_mask(map, mp);
 
 	if (auxtrace_mmap__mmap(&map->auxtrace_mmap,
 				&mp->auxtrace_mp, map->base, fd))
diff --git a/tools/perf/util/mmap.h b/tools/perf/util/mmap.h
index e566c19b242b..b3f724fad22e 100644
--- a/tools/perf/util/mmap.h
+++ b/tools/perf/util/mmap.h
@@ -72,6 +72,7 @@ enum bkw_mmap_state {
 struct mmap_params {
 	int			    prot, mask, nr_cblocks, affinity;
 	struct auxtrace_mmap_params auxtrace_mp;
+	const struct cpu_map	    *cpu_map;
 };
 
 int perf_mmap__mmap(struct perf_mmap *map, struct mmap_params *mp, int fd, int cpu);