* [PATCH v2] perf evlist: Avoid iteration for empty evlist.
@ 2022-03-17 23:16 Ian Rogers
2022-03-18 14:26 ` Arnaldo Carvalho de Melo
2022-03-18 20:40 ` Jiri Olsa
0 siblings, 2 replies; 3+ messages in thread
From: Ian Rogers @ 2022-03-17 23:16 UTC (permalink / raw)
To: Arnaldo Carvalho de Melo, Namhyung Kim, Jiri Olsa, Adrian Hunter,
Linux Kernel Mailing List
Cc: Ian Rogers
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 <jolsa@kernel.org>.
Fixes: 472832d2c000 ("perf evlist: Refactor evlist__for_each_cpu()")
Signed-off-by: Ian Rogers <irogers@google.com>
---
tools/perf/util/evlist.c | 28 +++++++++++++++++-----------
1 file changed, 17 insertions(+), 11 deletions(-)
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 8134d45e2164..9bb79e049957 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -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;
}
--
2.35.1.894.gb6a874cedc-goog
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH v2] perf evlist: Avoid iteration for empty evlist.
2022-03-17 23:16 [PATCH v2] perf evlist: Avoid iteration for empty evlist Ian Rogers
@ 2022-03-18 14:26 ` Arnaldo Carvalho de Melo
2022-03-18 20:40 ` Jiri Olsa
1 sibling, 0 replies; 3+ messages in thread
From: Arnaldo Carvalho de Melo @ 2022-03-18 14:26 UTC (permalink / raw)
To: Ian Rogers
Cc: Namhyung Kim, Jiri Olsa, Adrian Hunter, Linux Kernel Mailing List
Em Thu, Mar 17, 2022 at 04:16:43PM -0700, Ian Rogers escreveu:
> 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 <jolsa@kernel.org>.
> Fixes: 472832d2c000 ("perf evlist: Refactor evlist__for_each_cpu()")
> Signed-off-by: Ian Rogers <irogers@google.com>
Thanks, replaced v1 with this new one.
- Arnaldo
> ---
> tools/perf/util/evlist.c | 28 +++++++++++++++++-----------
> 1 file changed, 17 insertions(+), 11 deletions(-)
>
> diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
> index 8134d45e2164..9bb79e049957 100644
> --- a/tools/perf/util/evlist.c
> +++ b/tools/perf/util/evlist.c
> @@ -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;
> }
> --
> 2.35.1.894.gb6a874cedc-goog
--
- Arnaldo
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH v2] perf evlist: Avoid iteration for empty evlist.
2022-03-17 23:16 [PATCH v2] perf evlist: Avoid iteration for empty evlist Ian Rogers
2022-03-18 14:26 ` Arnaldo Carvalho de Melo
@ 2022-03-18 20:40 ` Jiri Olsa
1 sibling, 0 replies; 3+ messages in thread
From: Jiri Olsa @ 2022-03-18 20:40 UTC (permalink / raw)
To: Ian Rogers
Cc: Arnaldo Carvalho de Melo, Namhyung Kim, Jiri Olsa, Adrian Hunter,
Linux Kernel Mailing List
On Thu, Mar 17, 2022 at 04:16:43PM -0700, Ian Rogers wrote:
> 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 <jolsa@kernel.org>.
> Fixes: 472832d2c000 ("perf evlist: Refactor evlist__for_each_cpu()")
> Signed-off-by: Ian Rogers <irogers@google.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
thanks,
jirka
> ---
> tools/perf/util/evlist.c | 28 +++++++++++++++++-----------
> 1 file changed, 17 insertions(+), 11 deletions(-)
>
> diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
> index 8134d45e2164..9bb79e049957 100644
> --- a/tools/perf/util/evlist.c
> +++ b/tools/perf/util/evlist.c
> @@ -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;
> }
> --
> 2.35.1.894.gb6a874cedc-goog
>
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2022-03-17 23:16 [PATCH v2] perf evlist: Avoid iteration for empty evlist Ian Rogers
2022-03-18 14:26 ` Arnaldo Carvalho de Melo
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