[PATCH RFC 18/21] libperf evlist: Allow mixing per-thread and per-cpu mmaps

Adrian Hunter
2022-04-22T16:26:17Z

mmap_per_evsel() will skip events that do not match the CPU, so all CPUs
can be iterated in any case.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
tools/lib/perf/evlist.c | 34 +++++-----------------------------
1 file changed, 5 insertions(+), 29 deletions(-)

diff --git a/tools/lib/perf/evlist.c b/tools/lib/perf/evlist.c
index 048b546f9444..37dfa9d936a7 100644
--- a/tools/lib/perf/evlist.c
+++ b/tools/lib/perf/evlist.c
@@ -508,29 +508,6 @@ mmap_per_evsel(struct perf_evlist *evlist, struct perf_evlist_mmap_ops *ops,
return 0;
}

-static int
-mmap_per_thread(struct perf_evlist *evlist, struct perf_evlist_mmap_ops *ops,
- struct perf_mmap_param *mp)
-{
- int thread;
- int nr_threads = perf_thread_map__nr(evlist->threads);
-
- for (thread = 0; thread < nr_threads; thread++) {
- int output = -1;
- int output_overwrite = -1;
-
- if (mmap_per_evsel(evlist, ops, thread, mp, 0, thread,
- &output, &output_overwrite))
- goto out_unmap;
- }
-
- return 0;
-
-out_unmap:
- perf_evlist__munmap(evlist);
- return -1;
-}
-
static int
mmap_per_cpu(struct perf_evlist *evlist, struct perf_evlist_mmap_ops *ops,
struct perf_mmap_param *mp)
@@ -561,9 +538,12 @@ static int perf_evlist__nr_mmaps(struct perf_evlist *evlist)
{
int nr_mmaps;

+ /* One for each CPU */
nr_mmaps = perf_cpu_map__nr(evlist->all_cpus);
- if (perf_cpu_map__empty(evlist->all_cpus))
- nr_mmaps = perf_thread_map__nr(evlist->threads);
+ /* One for each thread */
+ nr_mmaps += perf_thread_map__nr(evlist->threads);
+ /* Minus the dummy CPU or dummy thread */
+ nr_mmaps -= 1;

return nr_mmaps;
}
@@ -573,7 +553,6 @@ int perf_evlist__mmap_ops(struct perf_evlist *evlist,
struct perf_mmap_param *mp)
{
struct perf_evsel *evsel;
- const struct perf_cpu_map *cpus = evlist->all_cpus;

if (!ops || !ops->get || !ops->mmap)
return -EINVAL;
@@ -592,9 +571,6 @@ int perf_evlist__mmap_ops(struct perf_evlist *evlist,
if (evlist->pollfd.entries == NULL && perf_evlist__alloc_pollfd(evlist) < 0)
return -ENOMEM;

- if (perf_cpu_map__empty(cpus))
- return mmap_per_thread(evlist, ops, mp);
-
return mmap_per_cpu(evlist, ops, mp);
}

--
2.25.1