2023-06-22 05:24:21

by Ian Rogers

[permalink] [raw]
Subject: [PATCH v1 1/2] perf pmus: Add notion of default PMU for JSON events

JSON events created in pmu-events.c by jevents.py may not specify a
PMU they are associated with, in which case it is implied that it is
the first core PMU. Care is needed to select this for regular 'cpu',
s390 'cpum_cf' and ARMs many names as at the point the name is first
needed the core PMUs list hasn't been initialized. Add a helper in
perf_pmus to create this value, in the worst case by scanning sysfs.

Signed-off-by: Ian Rogers <[email protected]>
---
tools/perf/util/pmu.c | 35 ++++++++++++++++-------------------
tools/perf/util/pmus.c | 31 +++++++++++++++++++++++++++++++
tools/perf/util/pmus.h | 1 +
3 files changed, 48 insertions(+), 19 deletions(-)

diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index 6142e4710a2f..963c12f910c5 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -741,9 +741,11 @@ static bool pmu_uncore_alias_match(const char *pmu_name, const char *name)
}

struct pmu_add_cpu_aliases_map_data {
+ /* List being added to. */
struct list_head *head;
- const char *name;
- const char *cpu_name;
+ /* If a pmu_event lacks a given PMU the default used. */
+ char *default_pmu_name;
+ /* The PMU that we're searching for events for. */
struct perf_pmu *pmu;
};

@@ -752,37 +754,32 @@ static int pmu_add_cpu_aliases_map_callback(const struct pmu_event *pe,
void *vdata)
{
struct pmu_add_cpu_aliases_map_data *data = vdata;
- const char *pname = pe->pmu ? pe->pmu : data->cpu_name;
+ const char *pname = pe->pmu ?: data->default_pmu_name;

- if (data->pmu->is_uncore && pmu_uncore_alias_match(pname, data->name))
- goto new_alias;
-
- if (strcmp(pname, data->name))
- return 0;
-
-new_alias:
- /* need type casts to override 'const' */
- __perf_pmu__new_alias(data->head, -1, (char *)pe->name, (char *)pe->desc,
- (char *)pe->event, pe);
+ if (!strcmp(pname, data->pmu->name) ||
+ (data->pmu->is_uncore && pmu_uncore_alias_match(pname, data->pmu->name))) {
+ /* need type casts to override 'const' */
+ __perf_pmu__new_alias(data->head, -1, (char *)pe->name, (char *)pe->desc,
+ (char *)pe->event, pe);
+ }
return 0;
}

/*
- * From the pmu_events_map, find the table of PMU events that corresponds
- * to the current running CPU. Then, add all PMU events from that table
- * as aliases.
+ * From the pmu_events_table, find the events that correspond to the given
+ * PMU and add them to the list 'head'.
*/
void pmu_add_cpu_aliases_table(struct list_head *head, struct perf_pmu *pmu,
- const struct pmu_events_table *table)
+ const struct pmu_events_table *table)
{
struct pmu_add_cpu_aliases_map_data data = {
.head = head,
- .name = pmu->name,
- .cpu_name = is_sysfs_pmu_core(pmu->name) ? pmu->name : "cpu",
+ .default_pmu_name = perf_pmus__default_pmu_name(),
.pmu = pmu,
};

pmu_events_table_for_each_event(table, pmu_add_cpu_aliases_map_callback, &data);
+ free(data.default_pmu_name);
}

static void pmu_add_cpu_aliases(struct list_head *head, struct perf_pmu *pmu)
diff --git a/tools/perf/util/pmus.c b/tools/perf/util/pmus.c
index d891d72c824e..80797e1b862f 100644
--- a/tools/perf/util/pmus.c
+++ b/tools/perf/util/pmus.c
@@ -524,6 +524,37 @@ bool perf_pmus__supports_extended_type(void)
return perf_pmus__do_support_extended_type;
}

+char *perf_pmus__default_pmu_name(void)
+{
+ int fd;
+ DIR *dir;
+ struct dirent *dent;
+ char *result = NULL;
+
+ if (!list_empty(&core_pmus))
+ return strdup(list_first_entry(&core_pmus, struct perf_pmu, list)->name);
+
+ fd = perf_pmu__event_source_devices_fd();
+ if (fd < 0)
+ return strdup("cpu");
+
+ dir = fdopendir(fd);
+ if (!dir)
+ return strdup("cpu");
+
+ while ((dent = readdir(dir))) {
+ if (!strcmp(dent->d_name, ".") || !strcmp(dent->d_name, ".."))
+ continue;
+ if (is_pmu_core(dent->d_name)) {
+ result = strdup(dent->d_name);
+ break;
+ }
+ }
+
+ closedir(dir);
+ return result ?: strdup("cpu");
+}
+
struct perf_pmu *evsel__find_pmu(const struct evsel *evsel)
{
struct perf_pmu *pmu = evsel->pmu;
diff --git a/tools/perf/util/pmus.h b/tools/perf/util/pmus.h
index d02ffea5d3a4..a21464432d0f 100644
--- a/tools/perf/util/pmus.h
+++ b/tools/perf/util/pmus.h
@@ -20,5 +20,6 @@ void perf_pmus__print_pmu_events(const struct print_callbacks *print_cb, void *p
bool perf_pmus__have_event(const char *pname, const char *name);
int perf_pmus__num_core_pmus(void);
bool perf_pmus__supports_extended_type(void);
+char *perf_pmus__default_pmu_name(void);

#endif /* __PMUS_H */
--
2.41.0.162.gfafddb0af9-goog



2023-06-22 22:33:56

by Namhyung Kim

[permalink] [raw]
Subject: Re: [PATCH v1 1/2] perf pmus: Add notion of default PMU for JSON events

On Wed, Jun 21, 2023 at 10:03 PM Ian Rogers <[email protected]> wrote:
>
> JSON events created in pmu-events.c by jevents.py may not specify a
> PMU they are associated with, in which case it is implied that it is
> the first core PMU. Care is needed to select this for regular 'cpu',
> s390 'cpum_cf' and ARMs many names as at the point the name is first
> needed the core PMUs list hasn't been initialized. Add a helper in
> perf_pmus to create this value, in the worst case by scanning sysfs.
>
> Signed-off-by: Ian Rogers <[email protected]>
> ---

[SNIP]
> diff --git a/tools/perf/util/pmus.c b/tools/perf/util/pmus.c
> index d891d72c824e..80797e1b862f 100644
> --- a/tools/perf/util/pmus.c
> +++ b/tools/perf/util/pmus.c
> @@ -524,6 +524,37 @@ bool perf_pmus__supports_extended_type(void)
> return perf_pmus__do_support_extended_type;
> }
>
> +char *perf_pmus__default_pmu_name(void)
> +{
> + int fd;
> + DIR *dir;
> + struct dirent *dent;
> + char *result = NULL;
> +
> + if (!list_empty(&core_pmus))
> + return strdup(list_first_entry(&core_pmus, struct perf_pmu, list)->name);
> +
> + fd = perf_pmu__event_source_devices_fd();
> + if (fd < 0)
> + return strdup("cpu");
> +
> + dir = fdopendir(fd);
> + if (!dir)
> + return strdup("cpu");

close(fd) ?

Thanks,
Namhyung


> +
> + while ((dent = readdir(dir))) {
> + if (!strcmp(dent->d_name, ".") || !strcmp(dent->d_name, ".."))
> + continue;
> + if (is_pmu_core(dent->d_name)) {
> + result = strdup(dent->d_name);
> + break;
> + }
> + }
> +
> + closedir(dir);
> + return result ?: strdup("cpu");
> +}
> +
> struct perf_pmu *evsel__find_pmu(const struct evsel *evsel)
> {
> struct perf_pmu *pmu = evsel->pmu;
> diff --git a/tools/perf/util/pmus.h b/tools/perf/util/pmus.h
> index d02ffea5d3a4..a21464432d0f 100644
> --- a/tools/perf/util/pmus.h
> +++ b/tools/perf/util/pmus.h
> @@ -20,5 +20,6 @@ void perf_pmus__print_pmu_events(const struct print_callbacks *print_cb, void *p
> bool perf_pmus__have_event(const char *pname, const char *name);
> int perf_pmus__num_core_pmus(void);
> bool perf_pmus__supports_extended_type(void);
> +char *perf_pmus__default_pmu_name(void);
>
> #endif /* __PMUS_H */
> --
> 2.41.0.162.gfafddb0af9-goog
>