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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: Jiri Olsa <jolsa@kernel.org>
Requested-by: Shunsuke 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: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Jiri Olsa 2021-07-06 17:17:03 +02:00 committed by Arnaldo Carvalho de Melo
parent c47a5599ed
commit 3fd35de168
1 changed files with 24 additions and 2 deletions
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26
tools/lib/perf/evsel.c
View File

@ -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;