Commit 3fd35de1 authored by Jiri Olsa's avatar Jiri Olsa Committed by Arnaldo Carvalho de Melo
Browse files

libperf: Add group support to perf_evsel__open() 



Add support to set group_fd in perf_evsel__open() and make it follow the
group setup.

Signed-off-by: default avatarJiri Olsa <jolsa@kernel.org>
Requested-by: default avatarShunsuke Nakamura <nakamura.shun@fujitsu.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20210706151704.73662-7-jolsa@kernel.org


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent c47a5599

tools/lib/perf/evsel.c

+24 −2
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 
#include <linux/string.h>

#include <sys/ioctl.h>

#include <sys/mman.h>

#include <asm/bug.h>



void perf_evsel__init(struct perf_evsel *evsel, struct perf_event_attr *attr,

		      int idx)
@@ -76,6 +77,25 @@ sys_perf_event_open(struct perf_event_attr *attr, 
	return syscall(__NR_perf_event_open, attr, pid, cpu, group_fd, flags);

}



static int get_group_fd(struct perf_evsel *evsel, int cpu, int thread)

{

	struct perf_evsel *leader = evsel->leader;

	int fd;



	if (evsel == leader)

		return -1;



	/*

	 * Leader must be already processed/open,

	 * if not it's a bug.

	 */

	BUG_ON(!leader->fd);



	fd = FD(leader, cpu, thread);

	BUG_ON(fd == -1);

	return fd;

}



int perf_evsel__open(struct perf_evsel *evsel, struct perf_cpu_map *cpus,

		     struct perf_thread_map *threads)

{
@@ -111,11 +131,13 @@ int perf_evsel__open(struct perf_evsel *evsel, struct perf_cpu_map *cpus, 


	for (cpu = 0; cpu < cpus->nr; cpu++) {

		for (thread = 0; thread < threads->nr; thread++) {

			int fd;

			int fd, group_fd;



			group_fd = get_group_fd(evsel, cpu, thread);



			fd = sys_perf_event_open(&evsel->attr,

						 threads->map[thread].pid,

						 cpus->map[cpu], -1, 0);

						 cpus->map[cpu], group_fd, 0);



			if (fd < 0)

				return -errno;