UbiquitousOS
/
OpenCloudOS-Kernel
mirror of https://gitee.com/OpenCloudOS/OpenCloudOS-Kernel.git
11
0
Fork 0
Code Issues Projects Releases Wiki Activity

perf evlist: Avoid iteration for empty evlist. 

As seen with 'perf stat --null ..' and reported in:
https://lore.kernel.org/lkml/YjCLcpcX2peeQVCH@kernel.org/

v2. Avoids setting evsel in the empty list case as suggested by Jiri Olsa.

    Committer testing:

Before:

  $  perf stat --null sleep 1
  Segmentation fault (core dumped)
  $

After:

  $  perf stat --null sleep 1

   Performance counter stats for 'sleep 1':

         1.010340646 seconds time elapsed

         0.001420000 seconds user
         0.000000000 seconds sys
  $

Fixes: 472832d2c0 ("perf evlist: Refactor evlist__for_each_cpu()")
Reported-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20220317231643.550902-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Ian Rogers 2022-03-17 16:16:43 -07:00 committed by Arnaldo Carvalho de Melo
parent 3cf6a32f3f
commit 8b464eac97
1 changed files with 17 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
tools/perf/util/evlist.c
View File

@ -346,7 +346,7 @@ struct evlist_cpu_iterator evlist__cpu_begin(struct evlist *evlist, struct affin
{
struct evlist_cpu_iterator itr = {
.container = evlist,
.evsel = evlist__first(evlist),
.evsel = NULL,
.cpu_map_idx = 0,
.evlist_cpu_map_idx = 0,
.evlist_cpu_map_nr = perf_cpu_map__nr(evlist->core.all_cpus),
@ -354,16 +354,22 @@ struct evlist_cpu_iterator evlist__cpu_begin(struct evlist *evlist, struct affin
.affinity = affinity,
};
if (itr.affinity) {
itr.cpu = perf_cpu_map__cpu(evlist->core.all_cpus, 0);
affinity__set(itr.affinity, itr.cpu.cpu);
itr.cpu_map_idx = perf_cpu_map__idx(itr.evsel->core.cpus, itr.cpu);
/*
* If this CPU isn't in the evsel's cpu map then advance through
* the list.
*/
if (itr.cpu_map_idx == -1)
evlist_cpu_iterator__next(&itr);
if (evlist__empty(evlist)) {
/* Ensure the empty list doesn't iterate. */
itr.evlist_cpu_map_idx = itr.evlist_cpu_map_nr;
} else {
itr.evsel = evlist__first(evlist);
if (itr.affinity) {
itr.cpu = perf_cpu_map__cpu(evlist->core.all_cpus, 0);
affinity__set(itr.affinity, itr.cpu.cpu);
itr.cpu_map_idx = perf_cpu_map__idx(itr.evsel->core.cpus, itr.cpu);
/*
* If this CPU isn't in the evsel's cpu map then advance
* through the list.
*/
if (itr.cpu_map_idx == -1)
evlist_cpu_iterator__next(&itr);
}
}
return itr;
}