Commit ec8149fb authored by Song Liu's avatar Song Liu Committed by Arnaldo Carvalho de Melo
Browse files

perf util: Move bpf_perf definitions to a libperf header 



By following the same protocol, other tools can share hardware PMCs with
perf. Move perf_event_attr_map_entry and BPF_PERF_DEFAULT_ATTR_MAP_PATH to
bpf_perf.h for other tools to use.

Signed-off-by: default avatarSong Liu <song@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: kernel-team@fb.com
Link: https://lore.kernel.org/r/20210425214333.1090950-2-song@kernel.org


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 26bda3ca

tools/lib/perf/include/perf/bpf_perf.h

0 → 100644
+31 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */

#ifndef __LIBPERF_BPF_PERF_H

#define __LIBPERF_BPF_PERF_H



#include <linux/types.h>  /* for __u32 */



/*

 * bpf_perf uses a hashmap, the attr_map, to track all the leader programs.

 * The hashmap is pinned in bpffs. flock() on this file is used to ensure

 * no concurrent access to the attr_map.  The key of attr_map is struct

 * perf_event_attr, and the value is struct perf_event_attr_map_entry.

 *

 * struct perf_event_attr_map_entry contains two __u32 IDs, bpf_link of the

 * leader prog, and the diff_map. Each perf-stat session holds a reference

 * to the bpf_link to make sure the leader prog is attached to sched_switch

 * tracepoint.

 *

 * Since the hashmap only contains IDs of the bpf_link and diff_map, it

 * does not hold any references to the leader program. Once all perf-stat

 * sessions of these events exit, the leader prog, its maps, and the

 * perf_events will be freed.

 */

struct perf_event_attr_map_entry {

	__u32 link_id;

	__u32 diff_map_id;

};



/* default attr_map name */

#define BPF_PERF_DEFAULT_ATTR_MAP_PATH "perf_attr_map"



#endif /* __LIBPERF_BPF_PERF_H */

tools/perf/util/bpf_counter.c

+3 −24
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ 
#include <bpf/btf.h>

#include <bpf/libbpf.h>

#include <api/fs/fs.h>

#include <perf/bpf_perf.h>



#include "bpf_counter.h"

#include "counts.h"
@@ -29,28 +30,6 @@ 
#include "bpf_skel/bperf_leader.skel.h"

#include "bpf_skel/bperf_follower.skel.h"



/*

 * bperf uses a hashmap, the attr_map, to track all the leader programs.

 * The hashmap is pinned in bpffs. flock() on this file is used to ensure

 * no concurrent access to the attr_map.  The key of attr_map is struct

 * perf_event_attr, and the value is struct perf_event_attr_map_entry.

 *

 * struct perf_event_attr_map_entry contains two __u32 IDs, bpf_link of the

 * leader prog, and the diff_map. Each perf-stat session holds a reference

 * to the bpf_link to make sure the leader prog is attached to sched_switch

 * tracepoint.

 *

 * Since the hashmap only contains IDs of the bpf_link and diff_map, it

 * does not hold any references to the leader program. Once all perf-stat

 * sessions of these events exit, the leader prog, its maps, and the

 * perf_events will be freed.

 */

struct perf_event_attr_map_entry {

	__u32 link_id;

	__u32 diff_map_id;

};



#define DEFAULT_ATTR_MAP_PATH "fs/bpf/perf_attr_map"

#define ATTR_MAP_SIZE 16



static inline void *u64_to_ptr(__u64 ptr)
@@ -341,8 +320,8 @@ static int bperf_lock_attr_map(struct target *target) 
	if (target->attr_map) {

		scnprintf(path, PATH_MAX, "%s", target->attr_map);

	} else {

		scnprintf(path, PATH_MAX, "%s/%s", sysfs__mountpoint(),

			  DEFAULT_ATTR_MAP_PATH);

		scnprintf(path, PATH_MAX, "%s/fs/bpf/%s", sysfs__mountpoint(),

			  BPF_PERF_DEFAULT_ATTR_MAP_PATH);

	}



	if (access(path, F_OK)) {