Re: [PATCH v7 05/16] perf tp_pmu: Add event APIs

[Arnaldo Carvalho de Melo <acme@kernel.org>]

On Mon, Jul 14, 2025 at 09:43:53AM -0700, Ian Rogers wrote:
> Add event APIs for the tracepoint PMU allowing things like perf list
> to function using it. For perf list add the tracepoint format in the
> long description (shown with -v).
> 
> Signed-off-by: Ian Rogers <irogers@google.com>
> ---
>  tools/perf/util/pmu.c    |   7 +++
>  tools/perf/util/tp_pmu.c | 114 +++++++++++++++++++++++++++++++++++++++
>  tools/perf/util/tp_pmu.h |   7 +++
>  3 files changed, 128 insertions(+)
> 
> diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
> index b09b2ea2407a..dc05233e8232 100644
> --- a/tools/perf/util/pmu.c
> +++ b/tools/perf/util/pmu.c
> @@ -24,6 +24,7 @@
>  #include "hwmon_pmu.h"
>  #include "pmus.h"
>  #include "tool_pmu.h"
> +#include "tp_pmu.h"
>  #include <util/pmu-bison.h>
>  #include <util/pmu-flex.h>
>  #include "parse-events.h"
> @@ -1983,6 +1984,8 @@ bool perf_pmu__have_event(struct perf_pmu *pmu, const char *name)
>  		return false;
>  	if (perf_pmu__is_tool(pmu) && tool_pmu__skip_event(name))
>  		return false;
> +	if (perf_pmu__is_tracepoint(pmu))
> +		return tp_pmu__have_event(pmu, name);
>  	if (perf_pmu__is_hwmon(pmu))
>  		return hwmon_pmu__have_event(pmu, name);
>  	if (perf_pmu__is_drm(pmu))
> @@ -1998,6 +2001,8 @@ size_t perf_pmu__num_events(struct perf_pmu *pmu)
>  {
>  	size_t nr;
>  
> +	if (perf_pmu__is_tracepoint(pmu))
> +		return tp_pmu__num_events(pmu);
>  	if (perf_pmu__is_hwmon(pmu))
>  		return hwmon_pmu__num_events(pmu);
>  	if (perf_pmu__is_drm(pmu))
> @@ -2068,6 +2073,8 @@ int perf_pmu__for_each_event(struct perf_pmu *pmu, bool skip_duplicate_pmus,
>  	struct hashmap_entry *entry;
>  	size_t bkt;
>  
> +	if (perf_pmu__is_tracepoint(pmu))
> +		return tp_pmu__for_each_event(pmu, state, cb);
>  	if (perf_pmu__is_hwmon(pmu))
>  		return hwmon_pmu__for_each_event(pmu, state, cb);
>  	if (perf_pmu__is_drm(pmu))
> diff --git a/tools/perf/util/tp_pmu.c b/tools/perf/util/tp_pmu.c
> index fd83164f8763..9d68a1da17f6 100644
> --- a/tools/perf/util/tp_pmu.c
> +++ b/tools/perf/util/tp_pmu.c
> @@ -1,5 +1,6 @@
>  // SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
>  #include "tp_pmu.h"
> +#include "pmus.h"
>  #include <api/fs/fs.h>
>  #include <api/fs/tracing_path.h>
>  #include <api/io_dir.h>
> @@ -93,3 +94,116 @@ int tp_pmu__for_each_tp_sys(void *state, tp_sys_callback cb)
>  	close(events_dir.dirfd);
>  	return ret;
>  }
> +
> +bool perf_pmu__is_tracepoint(const struct perf_pmu *pmu)
> +{
> +	return pmu->type == PERF_TYPE_TRACEPOINT;
> +}
> +
> +struct for_each_event_args {
> +	void *state;
> +	pmu_event_callback cb;
> +	const struct perf_pmu *pmu;
> +};
> +
> +static int for_each_event_cb(void *state, const char *sys_name, const char *evt_name)
> +{
> +	struct for_each_event_args *args = state;
> +	char name[2 * FILENAME_MAX + 2];
> +	/* 16 possible hex digits and 22 other characters and \0. */
> +	char encoding[16 + 22];
> +	char *format = NULL;
> +	size_t format_size;
> +	struct pmu_event_info info = {
> +		.pmu = args->pmu,
> +		.pmu_name = args->pmu->name,
> +		.event_type_desc = "Tracepoint event",
> +	};
> +	char *tp_dir = get_events_file(sys_name);
> +	char path[PATH_MAX];
> +	int id, err;
> +
> +	if (!tp_dir)
> +		return -1;
> +
> +	scnprintf(path, sizeof(path), "%s/%s/id", tp_dir, evt_name);
> +	err = filename__read_int(path, &id);
> +	if (err == 0) {
> +		snprintf(encoding, sizeof(encoding), "tracepoint/config=0x%x/", id);
> +		info.encoding_desc = encoding;
> +	}
> +
> +	scnprintf(path, sizeof(path), "%s/%s/format", tp_dir, evt_name);
> +	put_events_file(tp_dir);
> +	err = filename__read_str(path, &format, &format_size);
> +	if (err == 0) {
> +		info.long_desc = format;
> +		for (size_t i = 0 ; i < format_size; i++) {
> +			/* Swap tabs to spaces due to some rendering issues. */
> +			if (format[i] == '\t')
> +				format[i] = ' ';
> +		}
> +	}
> +	snprintf(name, sizeof(name), "%s:%s", sys_name, evt_name);
> +	info.name = name;
> +	err = args->cb(args->state, &info);
> +	free(format);
> +	return err;
> +}
> +
> +static int for_each_event_sys_cb(void *state, const char *sys_name)
> +{
> +	return tp_pmu__for_each_tp_event(sys_name, state, for_each_event_cb);
> +}
> +
> +int tp_pmu__for_each_event(struct perf_pmu *pmu, void *state, pmu_event_callback cb)
> +{
> +	struct for_each_event_args args = {
> +		.state = state,
> +		.cb = cb,
> +		.pmu = pmu,
> +	};
> +
> +	return tp_pmu__for_each_tp_sys(&args, for_each_event_sys_cb);
> +}
> +
> +static int num_events_cb(void *state, const char *sys_name __maybe_unused,
> +			 const char *evt_name __maybe_unused)
> +{
> +	size_t *count = state;
> +
> +	(*count)++;
> +	return 0;
> +}
> +
> +static int num_events_sys_cb(void *state, const char *sys_name)
> +{
> +	return tp_pmu__for_each_tp_event(sys_name, state, num_events_cb);
> +}
> +
> +size_t tp_pmu__num_events(struct perf_pmu *pmu __maybe_unused)
> +{
> +	size_t count = 0;
> +
> +	tp_pmu__for_each_tp_sys(&count, num_events_sys_cb);
> +	return count;
> +}
> +
> +bool tp_pmu__have_event(struct perf_pmu *pmu __maybe_unused, const char *name)
> +{
> +	char *dup_name, *colon;
> +	int id;
> +
> +	if (strchr(name, ':') == NULL)
> +		return false;

Nit:

	colon = strchr(name, ':');
	if (colon == NULL)
		return false;

> +
> +	dup_name = strdup(name);
> +	if (!dup_name)
> +		return false;
> +
> +	colon = strchr(dup_name, ':');

	colon = dup_name + (colon - name);

> +	*colon = '\0';
> +	id = tp_pmu__id(dup_name, colon + 1);
> +	free(dup_name);
> +	return id >= 0;
> +}
> diff --git a/tools/perf/util/tp_pmu.h b/tools/perf/util/tp_pmu.h
> index 49537303bd73..30456bd6943d 100644
> --- a/tools/perf/util/tp_pmu.h
> +++ b/tools/perf/util/tp_pmu.h
> @@ -2,6 +2,8 @@
>  #ifndef __TP_PMU_H
>  #define __TP_PMU_H
>  
> +#include "pmu.h"
> +
>  typedef int (*tp_sys_callback)(void *state, const char *sys_name);
>  typedef int (*tp_event_callback)(void *state, const char *sys_name, const char *evt_name);
>  
> @@ -9,4 +11,9 @@ int tp_pmu__id(const char *sys, const char *name);
>  int tp_pmu__for_each_tp_event(const char *sys, void *state, tp_event_callback cb);
>  int tp_pmu__for_each_tp_sys(void *state, tp_sys_callback cb);
>  
> +bool perf_pmu__is_tracepoint(const struct perf_pmu *pmu);
> +int tp_pmu__for_each_event(struct perf_pmu *pmu, void *state, pmu_event_callback cb);
> +size_t tp_pmu__num_events(struct perf_pmu *pmu);
> +bool tp_pmu__have_event(struct perf_pmu *pmu, const char *name);
> +
>  #endif /* __TP_PMU_H */
> -- 
> 2.50.0.727.gbf7dc18ff4-goog
>