Re: [PATCH 1/3] perf list: Check if libpfm4 event is supported

[Ian Rogers <irogers@google.com>]

On Thu, Jun 8, 2023 at 4:24 PM Namhyung Kim <namhyung@kernel.org> wrote:
>
> Some of its event info cannot be used directly due to missing default
> attributes.  Let's check if the event is supported before printing
> like we do for hw and cache events.
>
> Cc: Stephane Eranian <eranian@google.com>
> Signed-off-by: Namhyung Kim <namhyung@kernel.org>

Acked-by: Ian Rogers <irogers>@google.com>

Thanks,
Ian

> ---
>  tools/perf/util/pfm.c | 58 +++++++++++++++++++++++++++++++++++++------
>  1 file changed, 50 insertions(+), 8 deletions(-)
>
> diff --git a/tools/perf/util/pfm.c b/tools/perf/util/pfm.c
> index 076aecc22c16..4c1024c343dd 100644
> --- a/tools/perf/util/pfm.c
> +++ b/tools/perf/util/pfm.c
> @@ -13,6 +13,8 @@
>  #include "util/pmus.h"
>  #include "util/pfm.h"
>  #include "util/strbuf.h"
> +#include "util/cpumap.h"
> +#include "util/thread_map.h"
>
>  #include <string.h>
>  #include <linux/kernel.h>
> @@ -123,6 +125,36 @@ int parse_libpfm_events_option(const struct option *opt, const char *str,
>         return -1;
>  }
>
> +static bool is_libpfm_event_supported(const char *name, struct perf_cpu_map *cpus,
> +                                     struct perf_thread_map *threads)
> +{
> +       struct perf_pmu *pmu;
> +       struct evsel *evsel;
> +       struct perf_event_attr attr = {};
> +       bool result = true;
> +       int ret;
> +
> +       ret = pfm_get_perf_event_encoding(name, PFM_PLM0|PFM_PLM3,
> +                                         &attr, NULL, NULL);
> +       if (ret != PFM_SUCCESS)
> +               return false;
> +
> +       pmu = perf_pmus__find_by_type((unsigned int)attr.type);
> +       evsel = parse_events__add_event(0, &attr, name, /*metric_id=*/NULL, pmu);
> +       if (evsel == NULL)
> +               return false;
> +
> +       evsel->is_libpfm_event = true;
> +
> +       if (evsel__open(evsel, cpus, threads) < 0)
> +               result = false;
> +
> +       evsel__close(evsel);
> +       evsel__delete(evsel);
> +
> +       return result;
> +}
> +
>  static const char *srcs[PFM_ATTR_CTRL_MAX] = {
>         [PFM_ATTR_CTRL_UNKNOWN] = "???",
>         [PFM_ATTR_CTRL_PMU] = "PMU",
> @@ -146,6 +178,8 @@ print_libpfm_event(const struct print_callbacks *print_cb, void *print_state,
>  {
>         int j, ret;
>         char topic[80], name[80];
> +       struct perf_cpu_map *cpus = perf_cpu_map__empty_new(1);
> +       struct perf_thread_map *threads = thread_map__new_by_tid(0);
>
>         strbuf_setlen(buf, 0);
>         snprintf(topic, sizeof(topic), "pfm %s", pinfo->name);
> @@ -185,14 +219,15 @@ print_libpfm_event(const struct print_callbacks *print_cb, void *print_state,
>                                     ainfo.name, ainfo.desc);
>                 }
>         }
> -       print_cb->print_event(print_state,
> -                       pinfo->name,
> -                       topic,
> -                       name, info->equiv,
> -                       /*scale_unit=*/NULL,
> -                       /*deprecated=*/NULL, "PFM event",
> -                       info->desc, /*long_desc=*/NULL,
> -                       /*encoding_desc=*/buf->buf);
> +
> +       if (is_libpfm_event_supported(name, cpus, threads)) {
> +               print_cb->print_event(print_state, pinfo->name, topic,
> +                                     name, info->equiv,
> +                                     /*scale_unit=*/NULL,
> +                                     /*deprecated=*/NULL, "PFM event",
> +                                     info->desc, /*long_desc=*/NULL,
> +                                     /*encoding_desc=*/buf->buf);
> +       }
>
>         pfm_for_each_event_attr(j, info) {
>                 pfm_event_attr_info_t ainfo;
> @@ -215,6 +250,10 @@ print_libpfm_event(const struct print_callbacks *print_cb, void *print_state,
>                         print_attr_flags(buf, &ainfo);
>                         snprintf(name, sizeof(name), "%s::%s:%s",
>                                  pinfo->name, info->name, ainfo.name);
> +
> +                       if (!is_libpfm_event_supported(name, cpus, threads))
> +                               continue;
> +
>                         print_cb->print_event(print_state,
>                                         pinfo->name,
>                                         topic,
> @@ -225,6 +264,9 @@ print_libpfm_event(const struct print_callbacks *print_cb, void *print_state,
>                                         /*encoding_desc=*/buf->buf);
>                 }
>         }
> +
> +       perf_cpu_map__put(cpus);
> +       perf_thread_map__put(threads);
>  }
>
>  void print_libpfm_events(const struct print_callbacks *print_cb, void *print_state)
> --
> 2.41.0.162.gfafddb0af9-goog
>