perf cpu_map: Add cpu_map event synthesize function

Introduce the perf_event__synthesize_cpu_map function to synthesize a
struct cpu_map.

Added generic interface:
  cpu_map_data__alloc
  cpu_map_data__synthesize

to make the cpu_map synthesizing usable for other events.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Kan Liang <kan.liang@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1445784728-21732-9-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

2 files changed, 139 insertions, 0 deletions

diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c
index 719c0781a82a..15d6466a4b8f 100644
--- a/tools/perf/util/event.c
+++ b/tools/perf/util/event.c
@@ -737,6 +737,137 @@ int perf_event__synthesize_thread_map2(struct perf_tool *tool,
 	return err;
 }
 
+static void synthesize_cpus(struct cpu_map_entries *cpus,
+			    struct cpu_map *map)
+{
+	int i;
+
+	cpus->nr = map->nr;
+
+	for (i = 0; i < map->nr; i++)
+		cpus->cpu[i] = map->map[i];
+}
+
+static void synthesize_mask(struct cpu_map_mask *mask,
+			    struct cpu_map *map, int max)
+{
+	int i;
+
+	mask->nr = BITS_TO_LONGS(max);
+	mask->long_size = sizeof(long);
+
+	for (i = 0; i < map->nr; i++)
+		set_bit(map->map[i], mask->mask);
+}
+
+static size_t cpus_size(struct cpu_map *map)
+{
+	return sizeof(struct cpu_map_entries) + map->nr * sizeof(u16);
+}
+
+static size_t mask_size(struct cpu_map *map, int *max)
+{
+	int i;
+
+	*max = 0;
+
+	for (i = 0; i < map->nr; i++) {
+		/* bit possition of the cpu is + 1 */
+		int bit = map->map[i] + 1;
+
+		if (bit > *max)
+			*max = bit;
+	}
+
+	return sizeof(struct cpu_map_mask) + BITS_TO_LONGS(*max) * sizeof(long);
+}
+
+void *cpu_map_data__alloc(struct cpu_map *map, size_t *size, u16 *type, int *max)
+{
+	size_t size_cpus, size_mask;
+	bool is_dummy = cpu_map__empty(map);
+
+	/*
+	 * Both array and mask data have variable size based
+	 * on the number of cpus and their actual values.
+	 * The size of the 'struct cpu_map_data' is:
+	 *
+	 *   array = size of 'struct cpu_map_entries' +
+	 *           number of cpus * sizeof(u64)
+	 *
+	 *   mask  = size of 'struct cpu_map_mask' +
+	 *           maximum cpu bit converted to size of longs
+	 *
+	 * and finaly + the size of 'struct cpu_map_data'.
+	 */
+	size_cpus = cpus_size(map);
+	size_mask = mask_size(map, max);
+
+	if (is_dummy || (size_cpus < size_mask)) {
+		*size += size_cpus;
+		*type  = PERF_CPU_MAP__CPUS;
+	} else {
+		*size += size_mask;
+		*type  = PERF_CPU_MAP__MASK;
+	}
+
+	*size += sizeof(struct cpu_map_data);
+	return zalloc(*size);
+}
+
+void cpu_map_data__synthesize(struct cpu_map_data *data, struct cpu_map *map,
+			      u16 type, int max)
+{
+	data->type = type;
+
+	switch (type) {
+	case PERF_CPU_MAP__CPUS:
+		synthesize_cpus((struct cpu_map_entries *) data->data, map);
+		break;
+	case PERF_CPU_MAP__MASK:
+		synthesize_mask((struct cpu_map_mask *) data->data, map, max);
+	default:
+		break;
+	};
+}
+
+static struct cpu_map_event* cpu_map_event__new(struct cpu_map *map)
+{
+	size_t size = sizeof(struct cpu_map_event);
+	struct cpu_map_event *event;
+	int max;
+	u16 type;
+
+	event = cpu_map_data__alloc(map, &size, &type, &max);
+	if (!event)
+		return NULL;
+
+	event->header.type = PERF_RECORD_CPU_MAP;
+	event->header.size = size;
+	event->data.type   = type;
+
+	cpu_map_data__synthesize(&event->data, map, type, max);
+	return event;
+}
+
+int perf_event__synthesize_cpu_map(struct perf_tool *tool,
+				   struct cpu_map *map,
+				   perf_event__handler_t process,
+				   struct machine *machine)
+{
+	struct cpu_map_event *event;
+	int err;
+
+	event = cpu_map_event__new(map);
+	if (!event)
+		return -ENOMEM;
+
+	err = process(tool, (union perf_event *) event, NULL, machine);
+
+	free(event);
+	return err;
+}
+
 size_t perf_event__fprintf_comm(union perf_event *event, FILE *fp)
 {
 	const char *s;
diff --git a/tools/perf/util/event.h b/tools/perf/util/event.h
index 1c82a0ebda73..de18ee0e9c96 100644
--- a/tools/perf/util/event.h
+++ b/tools/perf/util/event.h
@@ -425,6 +425,7 @@ void perf_event__print_totals(void);
 
 struct perf_tool;
 struct thread_map;
+struct cpu_map;
 
 typedef int (*perf_event__handler_t)(struct perf_tool *tool,
 				     union perf_event *event,
@@ -440,6 +441,10 @@ int perf_event__synthesize_thread_map2(struct perf_tool *tool,
 				      struct thread_map *threads,
 				      perf_event__handler_t process,
 				      struct machine *machine);
+int perf_event__synthesize_cpu_map(struct perf_tool *tool,
+				   struct cpu_map *cpus,
+				   perf_event__handler_t process,
+				   struct machine *machine);
 int perf_event__synthesize_threads(struct perf_tool *tool,
 				   perf_event__handler_t process,
 				   struct machine *machine, bool mmap_data,
@@ -550,4 +555,7 @@ size_t perf_event__fprintf(union perf_event *event, FILE *fp);
 u64 kallsyms__get_function_start(const char *kallsyms_filename,
 				 const char *symbol_name);
 
+void *cpu_map_data__alloc(struct cpu_map *map, size_t *size, u16 *type, int *max);
+void  cpu_map_data__synthesize(struct cpu_map_data *data, struct cpu_map *map,
+			       u16 type, int max);
 #endif /* __PERF_RECORD_H */