[PATCH 2/5] libperf: Propagate maps only if necessary

From: Namhyung Kim
Date: Mon Oct 03 2022 - 16:47:09 EST


The current code propagate evsel's cpu map settings to evlist when it's
added to an evlist. But the evlist->all_cpus and each evsel's cpus will
be updated in perf_evlist__set_maps() later. No need to do it before
evlist's cpus are set actually.

In fact it discards this intermediate all_cpus maps at the beginning
of perf_evlist__set_maps(). Let's not do this. It's only needed when
an evsel is added after the evlist cpu/thread maps are set.

Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
---
tools/lib/perf/evlist.c | 11 ++++-------
tools/lib/perf/include/internal/evlist.h | 1 +
2 files changed, 5 insertions(+), 7 deletions(-)

diff --git a/tools/lib/perf/evlist.c b/tools/lib/perf/evlist.c
index 187129652ab6..8ce92070086c 100644
--- a/tools/lib/perf/evlist.c
+++ b/tools/lib/perf/evlist.c
@@ -67,9 +67,7 @@ static void perf_evlist__propagate_maps(struct perf_evlist *evlist)
{
struct perf_evsel *evsel;

- /* Recomputing all_cpus, so start with a blank slate. */
- perf_cpu_map__put(evlist->all_cpus);
- evlist->all_cpus = NULL;
+ evlist->needs_map_propagation = true;

perf_evlist__for_each_evsel(evlist, evsel)
__perf_evlist__propagate_maps(evlist, evsel);
@@ -81,7 +79,9 @@ void perf_evlist__add(struct perf_evlist *evlist,
evsel->idx = evlist->nr_entries;
list_add_tail(&evsel->node, &evlist->entries);
evlist->nr_entries += 1;
- __perf_evlist__propagate_maps(evlist, evsel);
+
+ if (evlist->needs_map_propagation)
+ __perf_evlist__propagate_maps(evlist, evsel);
}

void perf_evlist__remove(struct perf_evlist *evlist,
@@ -177,9 +177,6 @@ void perf_evlist__set_maps(struct perf_evlist *evlist,
evlist->threads = perf_thread_map__get(threads);
}

- if (!evlist->all_cpus && cpus)
- evlist->all_cpus = perf_cpu_map__get(cpus);
-
perf_evlist__propagate_maps(evlist);
}

diff --git a/tools/lib/perf/include/internal/evlist.h b/tools/lib/perf/include/internal/evlist.h
index 6f89aec3e608..850f07070036 100644
--- a/tools/lib/perf/include/internal/evlist.h
+++ b/tools/lib/perf/include/internal/evlist.h
@@ -19,6 +19,7 @@ struct perf_evlist {
int nr_entries;
int nr_groups;
bool has_user_cpus;
+ bool needs_map_propagation;
/**
* The cpus passed from the command line or all online CPUs by
* default.
--
2.38.0.rc1.362.ged0d419d3c-goog