Re: [PATCH 2/4] perf tools: Add perf_event__synthesize_{start,stop}()

[Adrian Hunter]

On 16/09/22 20:59, Namhyung Kim wrote:
> These functions are to prepare and cleanup necessary work for synthesizing.
> It doesn't do anything yet but later patch will add it.
> 
> Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
> ---
>  tools/perf/builtin-inject.c        | 3 +++
>  tools/perf/builtin-record.c        | 3 +++
>  tools/perf/builtin-stat.c          | 2 ++
>  tools/perf/builtin-top.c           | 4 ++++
>  tools/perf/util/auxtrace.c         | 2 ++
>  tools/perf/util/synthetic-events.c | 8 ++++++++
>  tools/perf/util/synthetic-events.h | 3 +++
>  7 files changed, 25 insertions(+)
> 
> diff --git a/tools/perf/builtin-inject.c b/tools/perf/builtin-inject.c
> index e254f18986f7..2e91a887919b 100644
> --- a/tools/perf/builtin-inject.c
> +++ b/tools/perf/builtin-inject.c
> @@ -2368,9 +2368,12 @@ int cmd_inject(int argc, const char **argv)
>  	if (ret < 0)
>  		goto out_delete;
>  
> +	perf_event__synthesize_start();
> +
>  	ret = __cmd_inject(&inject);
>  
>  	guest_session__exit(&inject.guest_session);
> +	perf_event__synthesize_stop();

AFAICT perf inject synthesizes mmap events only for JIT and that is
open-coded in jitdump.c. i.e. perf_event__synthesize_start / stop
not needed

>  
>  out_delete:
>  	strlist__delete(inject.known_build_ids);
> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> index 02e38f50a138..5b7b9ad2a280 100644
> --- a/tools/perf/builtin-record.c
> +++ b/tools/perf/builtin-record.c
> @@ -1966,6 +1966,8 @@ static int record__synthesize(struct record *rec, bool tail)
>  	if (rec->opts.tail_synthesize != tail)
>  		return 0;
>  
> +	perf_event__synthesize_start();

Perhaps also record__synthesize_workload() ?

> +
>  	if (data->is_pipe) {
>  		err = perf_event__synthesize_for_pipe(tool, session, data,
>  						      process_synthesized_event);
> @@ -2072,6 +2074,7 @@ static int record__synthesize(struct record *rec, bool tail)
>  	}
>  
>  out:
> +	perf_event__synthesize_stop();
>  	return err;
>  }
>  
> diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
> index e05fe72c1d87..f6f61e08f4c2 100644
> --- a/tools/perf/builtin-stat.c
> +++ b/tools/perf/builtin-stat.c
> @@ -962,6 +962,7 @@ static int __run_perf_stat(int argc, const char **argv, int run_idx)
>  		if (err < 0)
>  			return err;
>  
> +		perf_event__synthesize_start();
>  		err = perf_event__synthesize_stat_events(&stat_config, NULL, evsel_list,
>  							 process_synthesized_event, is_pipe);
>  		if (err < 0)
> @@ -2641,6 +2642,7 @@ int cmd_stat(int argc, const char **argv)
>  			perf_session__write_header(perf_stat.session, evsel_list, fd, true);
>  		}
>  
> +		perf_event__synthesize_stop();
>  		evlist__close(evsel_list);
>  		perf_session__delete(perf_stat.session);
>  	}
> diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
> index e89208b4ad4b..1eff894e6b5f 100644
> --- a/tools/perf/builtin-top.c
> +++ b/tools/perf/builtin-top.c
> @@ -1258,6 +1258,8 @@ static int __cmd_top(struct perf_top *top)
>  #endif
>  	}
>  
> +	perf_event__synthesize_start();
> +
>  	ret = perf_event__synthesize_bpf_events(top->session, perf_event__process,
>  						&top->session->machines.host,
>  						&top->record_opts);
> @@ -1273,6 +1275,8 @@ static int __cmd_top(struct perf_top *top)
>  				    top->evlist->core.threads, true, false,
>  				    top->nr_threads_synthesize);
>  
> +	perf_event__synthesize_stop();
> +
>  	if (top->nr_threads_synthesize > 1)
>  		perf_set_singlethreaded();
>  
> diff --git a/tools/perf/util/auxtrace.c b/tools/perf/util/auxtrace.c
> index b59c278fe9ed..1bfe076c22fb 100644
> --- a/tools/perf/util/auxtrace.c
> +++ b/tools/perf/util/auxtrace.c
> @@ -1328,6 +1328,7 @@ int perf_event__process_auxtrace_info(struct perf_session *session,
>  	if (err)
>  		return err;
>  
> +	perf_event__synthesize_start();
>  	unleader_auxtrace(session);
>  
>  	return 0;
> @@ -2834,6 +2835,7 @@ void auxtrace__free(struct perf_session *session)
>  	if (!session->auxtrace)
>  		return;
>  
> +	perf_event__synthesize_stop();

auxtrace does not synthesize mmap events

>  	return session->auxtrace->free(session);
>  }
>  
> diff --git a/tools/perf/util/synthetic-events.c b/tools/perf/util/synthetic-events.c
> index 0ff57ca24577..9d4f5dacd154 100644
> --- a/tools/perf/util/synthetic-events.c
> +++ b/tools/perf/util/synthetic-events.c
> @@ -47,6 +47,14 @@
>  
>  unsigned int proc_map_timeout = DEFAULT_PROC_MAP_PARSE_TIMEOUT;
>  
> +void perf_event__synthesize_start(void)
> +{
> +}
> +
> +void perf_event__synthesize_stop(void)
> +{
> +}
> +
>  int perf_tool__process_synth_event(struct perf_tool *tool,
>  				   union perf_event *event,
>  				   struct machine *machine,
> diff --git a/tools/perf/util/synthetic-events.h b/tools/perf/util/synthetic-events.h
> index 53737d1619a4..e4414616080c 100644
> --- a/tools/perf/util/synthetic-events.h
> +++ b/tools/perf/util/synthetic-events.h
> @@ -43,6 +43,9 @@ int parse_synth_opt(char *str);
>  typedef int (*perf_event__handler_t)(struct perf_tool *tool, union perf_event *event,
>  				     struct perf_sample *sample, struct machine *machine);
>  
> +void perf_event__synthesize_start(void);
> +void perf_event__synthesize_stop(void);
> +
>  int perf_event__synthesize_attrs(struct perf_tool *tool, struct evlist *evlist, perf_event__handler_t process);
>  int perf_event__synthesize_attr(struct perf_tool *tool, struct perf_event_attr *attr, u32 ids, u64 *id, perf_event__handler_t process);
>  int perf_event__synthesize_build_id(struct perf_tool *tool, struct dso *pos, u16 misc, perf_event__handler_t process, struct machine *machine);