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Subject[RFC PATCH v1 15/37] perf evsel: separate open preparation from open itself
Date
This is a preparatory patch for the following patches with the goal to
separate in evlist__open_cpu the actual perf_event_open, which could be
performed in parallel, from the existing fallback mechanisms, which
should be handled sequentially.

This patch separates the first lines of evsel__open_cpu into a new
__evsel__prepare_open function.

Signed-off-by: Riccardo Mancini <rickyman7@gmail.com>
---
tools/perf/util/evsel.c | 45 +++++++++++++++++++++++++++++++----------
1 file changed, 34 insertions(+), 11 deletions(-)

diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 7b4bb3229a16524e..ddf324e2e17a0951 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -1746,22 +1746,20 @@ static int perf_event_open(struct evsel *evsel,
return fd;
}

-static int evsel__open_cpu(struct evsel *evsel, struct perf_cpu_map *cpus,
- struct perf_thread_map *threads,
- int start_cpu, int end_cpu)
+
+static struct perf_cpu_map *empty_cpu_map;
+static struct perf_thread_map *empty_thread_map;
+
+static int __evsel__prepare_open(struct evsel *evsel, struct perf_cpu_map *cpus,
+ struct perf_thread_map *threads)
{
- int cpu, thread, nthreads;
- unsigned long flags = PERF_FLAG_FD_CLOEXEC;
- int pid = -1, err, old_errno;
- enum { NO_CHANGE, SET_TO_MAX, INCREASED_MAX } set_rlimit = NO_CHANGE;
+ int nthreads;

if ((perf_missing_features.write_backward && evsel->core.attr.write_backward) ||
(perf_missing_features.aux_output && evsel->core.attr.aux_output))
return -EINVAL;

if (cpus == NULL) {
- static struct perf_cpu_map *empty_cpu_map;
-
if (empty_cpu_map == NULL) {
empty_cpu_map = perf_cpu_map__dummy_new();
if (empty_cpu_map == NULL)
@@ -1772,8 +1770,6 @@ static int evsel__open_cpu(struct evsel *evsel, struct perf_cpu_map *cpus,
}

if (threads == NULL) {
- static struct perf_thread_map *empty_thread_map;
-
if (empty_thread_map == NULL) {
empty_thread_map = thread_map__new_by_tid(-1);
if (empty_thread_map == NULL)
@@ -1792,6 +1788,33 @@ static int evsel__open_cpu(struct evsel *evsel, struct perf_cpu_map *cpus,
perf_evsel__alloc_fd(&evsel->core, cpus->nr, nthreads) < 0)
return -ENOMEM;

+ return 0;
+}
+
+static int evsel__open_cpu(struct evsel *evsel, struct perf_cpu_map *cpus,
+ struct perf_thread_map *threads,
+ int start_cpu, int end_cpu)
+{
+ int cpu, thread, nthreads;
+ unsigned long flags = PERF_FLAG_FD_CLOEXEC;
+ int pid = -1, err, old_errno;
+ enum { NO_CHANGE, SET_TO_MAX, INCREASED_MAX } set_rlimit = NO_CHANGE;
+
+ err = __evsel__prepare_open(evsel, cpus, threads);
+ if (err)
+ return err;
+
+ if (cpus == NULL)
+ cpus = empty_cpu_map;
+
+ if (threads == NULL)
+ threads = empty_thread_map;
+
+ if (evsel->core.system_wide)
+ nthreads = 1;
+ else
+ nthreads = threads->nr;
+
if (evsel->cgrp) {
flags |= PERF_FLAG_PID_CGROUP;
pid = evsel->cgrp->fd;
--
2.31.1
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