2023-03-02 22:01:35

by Ian Rogers

Subject: [PATCH v2 05/10] perf evsel: Allow const evsel for certain accesses

List sorting, added later to evlist, passes const elements requiring
helper functions to also be const. Make the argument to
evsel__find_pmu, evsel__is_aux_event and evsel__leader const.

Signed-off-by: Ian Rogers <[email protected]>
---
tools/perf/util/evsel.c | 2 +-
tools/perf/util/evsel.h | 6 +++---
tools/perf/util/pmu.c | 6 +++---
tools/perf/util/python.c | 2 +-
4 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 51e8ce6edddc..2dc2c24252bb 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -3139,7 +3139,7 @@ bool evsel__is_hybrid(const struct evsel *evsel)
return evsel->pmu_name && perf_pmu__is_hybrid(evsel->pmu_name);
}

-struct evsel *evsel__leader(struct evsel *evsel)
+struct evsel *evsel__leader(const struct evsel *evsel)
{
return container_of(evsel->core.leader, struct evsel, core);
}
diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
index 814a49ebb7e3..676c499323e9 100644
--- a/tools/perf/util/evsel.h
+++ b/tools/perf/util/evsel.h
@@ -212,8 +212,8 @@ int evsel__object_config(size_t object_size,
int (*init)(struct evsel *evsel),
void (*fini)(struct evsel *evsel));

-struct perf_pmu *evsel__find_pmu(struct evsel *evsel);
-bool evsel__is_aux_event(struct evsel *evsel);
+struct perf_pmu *evsel__find_pmu(const struct evsel *evsel);
+bool evsel__is_aux_event(const struct evsel *evsel);

struct evsel *evsel__new_idx(struct perf_event_attr *attr, int idx);

@@ -505,7 +505,7 @@ int evsel__store_ids(struct evsel *evsel, struct evlist *evlist);

void evsel__zero_per_pkg(struct evsel *evsel);
bool evsel__is_hybrid(const struct evsel *evsel);
-struct evsel *evsel__leader(struct evsel *evsel);
+struct evsel *evsel__leader(const struct evsel *evsel);
bool evsel__has_leader(struct evsel *evsel, struct evsel *leader);
bool evsel__is_leader(struct evsel *evsel);
void evsel__set_leader(struct evsel *evsel, struct evsel *leader);
diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index 43b6182d96b7..45d9b8e28e16 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -988,7 +988,7 @@ struct perf_pmu *perf_pmu__scan(struct perf_pmu *pmu)
return NULL;
}

-struct perf_pmu *evsel__find_pmu(struct evsel *evsel)
+struct perf_pmu *evsel__find_pmu(const struct evsel *evsel)
{
struct perf_pmu *pmu = NULL;

@@ -1000,11 +1000,11 @@ struct perf_pmu *evsel__find_pmu(struct evsel *evsel)
break;
}

- evsel->pmu = pmu;
+ ((struct evsel *)evsel)->pmu = pmu;
return pmu;
}

-bool evsel__is_aux_event(struct evsel *evsel)
+bool evsel__is_aux_event(const struct evsel *evsel)
{
struct perf_pmu *pmu = evsel__find_pmu(evsel);

diff --git a/tools/perf/util/python.c b/tools/perf/util/python.c
index 42e8b813d010..ab48ffbb6448 100644
--- a/tools/perf/util/python.c
+++ b/tools/perf/util/python.c
@@ -83,7 +83,7 @@ const char *perf_env__arch(struct perf_env *env __maybe_unused)
* far, for the perf python binding known usecases, revisit if this become
* necessary.
*/
-struct perf_pmu *evsel__find_pmu(struct evsel *evsel __maybe_unused)
+struct perf_pmu *evsel__find_pmu(const struct evsel *evsel __maybe_unused)
{
return NULL;
}
--
2.40.0.rc0.216.gc4246ad0f0-goog

2023-03-03 00:14:46

by Namhyung Kim

Subject: Re: [PATCH v2 05/10] perf evsel: Allow const evsel for certain accesses

Hi Ian,

On Thu, Mar 2, 2023 at 1:26 PM Ian Rogers <[email protected]> wrote:
>
> List sorting, added later to evlist, passes const elements requiring
> helper functions to also be const. Make the argument to
> evsel__find_pmu, evsel__is_aux_event and evsel__leader const.
>
> Signed-off-by: Ian Rogers <[email protected]>
> ---
> tools/perf/util/evsel.c | 2 +-
> tools/perf/util/evsel.h | 6 +++---
> tools/perf/util/pmu.c | 6 +++---
> tools/perf/util/python.c | 2 +-
> 4 files changed, 8 insertions(+), 8 deletions(-)
>
> diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
> index 51e8ce6edddc..2dc2c24252bb 100644
> --- a/tools/perf/util/evsel.c
> +++ b/tools/perf/util/evsel.c
> @@ -3139,7 +3139,7 @@ bool evsel__is_hybrid(const struct evsel *evsel)
> return evsel->pmu_name && perf_pmu__is_hybrid(evsel->pmu_name);
> }
>
> -struct evsel *evsel__leader(struct evsel *evsel)
> +struct evsel *evsel__leader(const struct evsel *evsel)

It seems like it should return const struct evsel *, right?

> {
> return container_of(evsel->core.leader, struct evsel, core);
> }
> diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
> index 814a49ebb7e3..676c499323e9 100644
> --- a/tools/perf/util/evsel.h
> +++ b/tools/perf/util/evsel.h
> @@ -212,8 +212,8 @@ int evsel__object_config(size_t object_size,
> int (*init)(struct evsel *evsel),
> void (*fini)(struct evsel *evsel));
>
> -struct perf_pmu *evsel__find_pmu(struct evsel *evsel);
> -bool evsel__is_aux_event(struct evsel *evsel);
> +struct perf_pmu *evsel__find_pmu(const struct evsel *evsel);
> +bool evsel__is_aux_event(const struct evsel *evsel);
>
> struct evsel *evsel__new_idx(struct perf_event_attr *attr, int idx);
>
> @@ -505,7 +505,7 @@ int evsel__store_ids(struct evsel *evsel, struct evlist *evlist);
>
> void evsel__zero_per_pkg(struct evsel *evsel);
> bool evsel__is_hybrid(const struct evsel *evsel);
> -struct evsel *evsel__leader(struct evsel *evsel);
> +struct evsel *evsel__leader(const struct evsel *evsel);
> bool evsel__has_leader(struct evsel *evsel, struct evsel *leader);
> bool evsel__is_leader(struct evsel *evsel);
> void evsel__set_leader(struct evsel *evsel, struct evsel *leader);
> diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
> index 43b6182d96b7..45d9b8e28e16 100644
> --- a/tools/perf/util/pmu.c
> +++ b/tools/perf/util/pmu.c
> @@ -988,7 +988,7 @@ struct perf_pmu *perf_pmu__scan(struct perf_pmu *pmu)
> return NULL;
> }
>
> -struct perf_pmu *evsel__find_pmu(struct evsel *evsel)
> +struct perf_pmu *evsel__find_pmu(const struct evsel *evsel)
> {
> struct perf_pmu *pmu = NULL;
>
> @@ -1000,11 +1000,11 @@ struct perf_pmu *evsel__find_pmu(struct evsel *evsel)
> break;
> }
>
> - evsel->pmu = pmu;
> + ((struct evsel *)evsel)->pmu = pmu;

Maybe we can move it out of the function and make callers set it.

Thanks,
Namhyung


> return pmu;
> }
>
> -bool evsel__is_aux_event(struct evsel *evsel)
> +bool evsel__is_aux_event(const struct evsel *evsel)
> {
> struct perf_pmu *pmu = evsel__find_pmu(evsel);
>
> diff --git a/tools/perf/util/python.c b/tools/perf/util/python.c
> index 42e8b813d010..ab48ffbb6448 100644
> --- a/tools/perf/util/python.c
> +++ b/tools/perf/util/python.c
> @@ -83,7 +83,7 @@ const char *perf_env__arch(struct perf_env *env __maybe_unused)
> * far, for the perf python binding known usecases, revisit if this become
> * necessary.
> */
> -struct perf_pmu *evsel__find_pmu(struct evsel *evsel __maybe_unused)
> +struct perf_pmu *evsel__find_pmu(const struct evsel *evsel __maybe_unused)
> {
> return NULL;
> }
> --
> 2.40.0.rc0.216.gc4246ad0f0-goog
>

2023-03-03 01:41:25

by Ian Rogers

Subject: Re: [PATCH v2 05/10] perf evsel: Allow const evsel for certain accesses

On Thu, Mar 2, 2023 at 4:14 PM Namhyung Kim <[email protected]> wrote:
>
> Hi Ian,
>
> On Thu, Mar 2, 2023 at 1:26 PM Ian Rogers <[email protected]> wrote:
> >
> > List sorting, added later to evlist, passes const elements requiring
> > helper functions to also be const. Make the argument to
> > evsel__find_pmu, evsel__is_aux_event and evsel__leader const.
> >
> > Signed-off-by: Ian Rogers <[email protected]>
> > ---
> > tools/perf/util/evsel.c | 2 +-
> > tools/perf/util/evsel.h | 6 +++---
> > tools/perf/util/pmu.c | 6 +++---
> > tools/perf/util/python.c | 2 +-
> > 4 files changed, 8 insertions(+), 8 deletions(-)
> >
> > diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
> > index 51e8ce6edddc..2dc2c24252bb 100644
> > --- a/tools/perf/util/evsel.c
> > +++ b/tools/perf/util/evsel.c
> > @@ -3139,7 +3139,7 @@ bool evsel__is_hybrid(const struct evsel *evsel)
> > return evsel->pmu_name && perf_pmu__is_hybrid(evsel->pmu_name);
> > }
> >
> > -struct evsel *evsel__leader(struct evsel *evsel)
> > +struct evsel *evsel__leader(const struct evsel *evsel)
>
> It seems like it should return const struct evsel *, right?

Yes, but that breaks things :-)

> > {
> > return container_of(evsel->core.leader, struct evsel, core);
> > }
> > diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
> > index 814a49ebb7e3..676c499323e9 100644
> > --- a/tools/perf/util/evsel.h
> > +++ b/tools/perf/util/evsel.h
> > @@ -212,8 +212,8 @@ int evsel__object_config(size_t object_size,
> > int (*init)(struct evsel *evsel),
> > void (*fini)(struct evsel *evsel));
> >
> > -struct perf_pmu *evsel__find_pmu(struct evsel *evsel);
> > -bool evsel__is_aux_event(struct evsel *evsel);
> > +struct perf_pmu *evsel__find_pmu(const struct evsel *evsel);
> > +bool evsel__is_aux_event(const struct evsel *evsel);
> >
> > struct evsel *evsel__new_idx(struct perf_event_attr *attr, int idx);
> >
> > @@ -505,7 +505,7 @@ int evsel__store_ids(struct evsel *evsel, struct evlist *evlist);
> >
> > void evsel__zero_per_pkg(struct evsel *evsel);
> > bool evsel__is_hybrid(const struct evsel *evsel);
> > -struct evsel *evsel__leader(struct evsel *evsel);
> > +struct evsel *evsel__leader(const struct evsel *evsel);
> > bool evsel__has_leader(struct evsel *evsel, struct evsel *leader);
> > bool evsel__is_leader(struct evsel *evsel);
> > void evsel__set_leader(struct evsel *evsel, struct evsel *leader);
> > diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
> > index 43b6182d96b7..45d9b8e28e16 100644
> > --- a/tools/perf/util/pmu.c
> > +++ b/tools/perf/util/pmu.c
> > @@ -988,7 +988,7 @@ struct perf_pmu *perf_pmu__scan(struct perf_pmu *pmu)
> > return NULL;
> > }
> >
> > -struct perf_pmu *evsel__find_pmu(struct evsel *evsel)
> > +struct perf_pmu *evsel__find_pmu(const struct evsel *evsel)
> > {
> > struct perf_pmu *pmu = NULL;
> >
> > @@ -1000,11 +1000,11 @@ struct perf_pmu *evsel__find_pmu(struct evsel *evsel)
> > break;
> > }
> >
> > - evsel->pmu = pmu;
> > + ((struct evsel *)evsel)->pmu = pmu;
>
> Maybe we can move it out of the function and make callers set it.

Right, I considered this a case where in C++ we'd use mutable so
casting away the const wasn't the worst offense.

Thanks,
Ian

> Thanks,
> Namhyung
>
>
> > return pmu;
> > }
> >
> > -bool evsel__is_aux_event(struct evsel *evsel)
> > +bool evsel__is_aux_event(const struct evsel *evsel)
> > {
> > struct perf_pmu *pmu = evsel__find_pmu(evsel);
> >
> > diff --git a/tools/perf/util/python.c b/tools/perf/util/python.c
> > index 42e8b813d010..ab48ffbb6448 100644
> > --- a/tools/perf/util/python.c
> > +++ b/tools/perf/util/python.c
> > @@ -83,7 +83,7 @@ const char *perf_env__arch(struct perf_env *env __maybe_unused)
> > * far, for the perf python binding known usecases, revisit if this become
> > * necessary.
> > */
> > -struct perf_pmu *evsel__find_pmu(struct evsel *evsel __maybe_unused)
> > +struct perf_pmu *evsel__find_pmu(const struct evsel *evsel __maybe_unused)
> > {
> > return NULL;
> > }
> > --
> > 2.40.0.rc0.216.gc4246ad0f0-goog
> >