Commit 147c508f authored by Jin Yao's avatar Jin Yao Committed by Arnaldo Carvalho de Melo
Browse files

perf tools: Use target->per_thread and target->system_wide flags 



Mathieu Poirier reports issue in commit ("73c0ca1e perf thread_map:
Enumerate all threads from /proc") that it has negative impact on 'perf
record --per-thread'. It has the effect of creating a kernel event for
each thread in the system for 'perf record --per-thread'.

Mathieu Poirier's patch ("perf util: Do not reuse target->per_thread flag")
can fix this issue by creating a new target->all_threads flag.

This patch is based on Mathieu Poirier's patch but it doesn't use a new
target->all_threads flag. This patch just uses 'target->per_thread &&
target->system_wide' as a condition to check for all threads case.

Signed-off-by: default avatarJin Yao <yao.jin@linux.intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-arm-kernel@lists.infradead.org
Fixes: 73c0ca1e ("perf thread_map: Enumerate all threads from /proc")
Link: http://lkml.kernel.org/r/1518467557-18505-3-git-send-email-mathieu.poirier@linaro.org


Signed-off-by: default avatarMathieu Poirier <mathieu.poirier@linaro.org>
[Fixed checkpatch warning about line over 80 characters]
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 099c1130

tools/perf/util/evlist.c

+20 −1
Original line number Diff line number Diff line
@@ -1086,11 +1086,30 @@ int perf_evlist__mmap(struct perf_evlist *evlist, unsigned int pages) 


int perf_evlist__create_maps(struct perf_evlist *evlist, struct target *target)

{

	bool all_threads = (target->per_thread && target->system_wide);

	struct cpu_map *cpus;

	struct thread_map *threads;



	/*

	 * If specify '-a' and '--per-thread' to perf record, perf record

	 * will override '--per-thread'. target->per_thread = false and

	 * target->system_wide = true.

	 *

	 * If specify '--per-thread' only to perf record,

	 * target->per_thread = true and target->system_wide = false.

	 *

	 * So target->per_thread && target->system_wide is false.

	 * For perf record, thread_map__new_str doesn't call

	 * thread_map__new_all_cpus. That will keep perf record's

	 * current behavior.

	 *

	 * For perf stat, it allows the case that target->per_thread and

	 * target->system_wide are all true. It means to collect system-wide

	 * per-thread data. thread_map__new_str will call

	 * thread_map__new_all_cpus to enumerate all threads.

	 */

	threads = thread_map__new_str(target->pid, target->tid, target->uid,

				      target->per_thread);

				      all_threads);



	if (!threads)

		return -1;

tools/perf/util/thread_map.c

+2 −2
Original line number Diff line number Diff line
@@ -323,7 +323,7 @@ struct thread_map *thread_map__new_by_tid_str(const char *tid_str) 
}



struct thread_map *thread_map__new_str(const char *pid, const char *tid,

				       uid_t uid, bool per_thread)

				       uid_t uid, bool all_threads)

{

	if (pid)

		return thread_map__new_by_pid_str(pid);
@@ -331,7 +331,7 @@ struct thread_map *thread_map__new_str(const char *pid, const char *tid, 
	if (!tid && uid != UINT_MAX)

		return thread_map__new_by_uid(uid);



	if (per_thread)

	if (all_threads)

		return thread_map__new_all_cpus();



	return thread_map__new_by_tid_str(tid);

tools/perf/util/thread_map.h

+1 −1
Original line number Diff line number Diff line
@@ -31,7 +31,7 @@ struct thread_map *thread_map__get(struct thread_map *map); 
void thread_map__put(struct thread_map *map);



struct thread_map *thread_map__new_str(const char *pid,

		const char *tid, uid_t uid, bool per_thread);

		const char *tid, uid_t uid, bool all_threads);



struct thread_map *thread_map__new_by_tid_str(const char *tid_str);