perf tools: Fix sparse CPU numbering related bugs
At present, the perf subcommands that do system-wide monitoring
(perf stat, perf record and perf top) don't work properly unless
the online cpus are numbered 0, 1, ..., N-1. These tools ask
for the number of online cpus with sysconf(_SC_NPROCESSORS_ONLN)
and then try to create events for cpus 0, 1, ..., N-1.
This creates problems for systems where the online cpus are
numbered sparsely. For example, a POWER6 system in
single-threaded mode (i.e. only running 1 hardware thread per
core) will have only even-numbered cpus online.
This fixes the problem by reading the /sys/devices/system/cpu/online
file to find out which cpus are online. The code that does that is in
tools/perf/util/cpumap.[ch], and consists of a read_cpu_map()
function that sets up a cpumap[] array and returns the number of
online cpus. If /sys/devices/system/cpu/online can't be read or
can't be parsed successfully, it falls back to using sysconf to
ask how many cpus are online and sets up an identity map in cpumap[].
The perf record, perf stat and perf top code then calls
read_cpu_map() in the system-wide monitoring case (instead of
sysconf) and uses cpumap[] to get the cpu numbers to pass to
perf_event_open.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Cc: Anton Blanchard <anton@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
LKML-Reference: <20100310093609.GA3959@brick.ozlabs.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-10 16:36:09 +07:00
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#ifndef __PERF_CPUMAP_H
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#define __PERF_CPUMAP_H
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2012-01-19 23:07:23 +07:00
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#include <stdio.h>
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2012-09-26 22:41:14 +07:00
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#include <stdbool.h>
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2015-06-23 05:36:04 +07:00
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#include <linux/atomic.h>
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2012-01-19 23:07:23 +07:00
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2014-04-08 01:55:21 +07:00
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#include "perf.h"
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#include "util/debug.h"
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2011-01-04 02:49:48 +07:00
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struct cpu_map {
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2015-06-23 05:36:04 +07:00
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atomic_t refcnt;
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2011-01-04 02:49:48 +07:00
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int nr;
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int map[];
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};
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struct cpu_map *cpu_map__new(const char *cpu_list);
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2015-10-25 21:51:17 +07:00
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struct cpu_map *cpu_map__empty_new(int nr);
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2011-01-04 02:49:48 +07:00
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struct cpu_map *cpu_map__dummy_new(void);
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2015-10-25 21:51:25 +07:00
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struct cpu_map *cpu_map__new_data(struct cpu_map_data *data);
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2012-09-10 14:53:50 +07:00
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struct cpu_map *cpu_map__read(FILE *file);
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2016-06-28 18:29:04 +07:00
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size_t cpu_map__snprint(struct cpu_map *map, char *buf, size_t size);
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2012-01-19 23:07:23 +07:00
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size_t cpu_map__fprintf(struct cpu_map *map, FILE *fp);
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2015-09-01 20:58:11 +07:00
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int cpu_map__get_socket_id(int cpu);
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2015-10-16 17:41:15 +07:00
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int cpu_map__get_socket(struct cpu_map *map, int idx, void *data);
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2015-09-01 20:58:11 +07:00
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int cpu_map__get_core_id(int cpu);
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2015-10-16 17:41:15 +07:00
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int cpu_map__get_core(struct cpu_map *map, int idx, void *data);
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2013-02-06 21:46:01 +07:00
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int cpu_map__build_socket_map(struct cpu_map *cpus, struct cpu_map **sockp);
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2013-02-14 19:57:29 +07:00
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int cpu_map__build_core_map(struct cpu_map *cpus, struct cpu_map **corep);
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2013-02-06 21:46:01 +07:00
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2015-06-23 05:36:04 +07:00
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struct cpu_map *cpu_map__get(struct cpu_map *map);
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void cpu_map__put(struct cpu_map *map);
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2013-02-06 21:46:01 +07:00
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static inline int cpu_map__socket(struct cpu_map *sock, int s)
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{
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if (!sock || s > sock->nr || s < 0)
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return 0;
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return sock->map[s];
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}
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2012-01-19 23:07:23 +07:00
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2013-02-14 19:57:29 +07:00
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static inline int cpu_map__id_to_socket(int id)
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{
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return id >> 16;
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}
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static inline int cpu_map__id_to_cpu(int id)
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{
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return id & 0xffff;
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}
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2012-09-26 22:41:14 +07:00
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static inline int cpu_map__nr(const struct cpu_map *map)
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{
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return map ? map->nr : 1;
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}
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2013-05-23 07:42:38 +07:00
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static inline bool cpu_map__empty(const struct cpu_map *map)
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2012-09-26 22:41:14 +07:00
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{
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return map ? map->map[0] == -1 : true;
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}
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2014-04-08 01:55:21 +07:00
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int cpu__setup_cpunode_map(void);
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2016-01-27 01:51:46 +07:00
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int cpu__max_node(void);
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int cpu__max_cpu(void);
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int cpu__get_node(int cpu);
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2014-04-08 01:55:21 +07:00
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2015-10-16 17:41:14 +07:00
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int cpu_map__build_map(struct cpu_map *cpus, struct cpu_map **res,
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2015-10-16 17:41:15 +07:00
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int (*f)(struct cpu_map *map, int cpu, void *data),
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void *data);
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2016-04-12 20:29:25 +07:00
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2016-07-15 17:08:11 +07:00
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int cpu_map__cpu(struct cpu_map *cpus, int idx);
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2016-04-12 20:29:25 +07:00
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bool cpu_map__has(struct cpu_map *cpus, int cpu);
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2016-07-15 17:08:11 +07:00
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int cpu_map__idx(struct cpu_map *cpus, int cpu);
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perf tools: Fix sparse CPU numbering related bugs
At present, the perf subcommands that do system-wide monitoring
(perf stat, perf record and perf top) don't work properly unless
the online cpus are numbered 0, 1, ..., N-1. These tools ask
for the number of online cpus with sysconf(_SC_NPROCESSORS_ONLN)
and then try to create events for cpus 0, 1, ..., N-1.
This creates problems for systems where the online cpus are
numbered sparsely. For example, a POWER6 system in
single-threaded mode (i.e. only running 1 hardware thread per
core) will have only even-numbered cpus online.
This fixes the problem by reading the /sys/devices/system/cpu/online
file to find out which cpus are online. The code that does that is in
tools/perf/util/cpumap.[ch], and consists of a read_cpu_map()
function that sets up a cpumap[] array and returns the number of
online cpus. If /sys/devices/system/cpu/online can't be read or
can't be parsed successfully, it falls back to using sysconf to
ask how many cpus are online and sets up an identity map in cpumap[].
The perf record, perf stat and perf top code then calls
read_cpu_map() in the system-wide monitoring case (instead of
sysconf) and uses cpumap[] to get the cpu numbers to pass to
perf_event_open.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Cc: Anton Blanchard <anton@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
LKML-Reference: <20100310093609.GA3959@brick.ozlabs.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-10 16:36:09 +07:00
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#endif /* __PERF_CPUMAP_H */
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