Re: [PATCH v4 06/11] perf evsel: Add function to compute group PMU name

[Arnaldo Carvalho de Melo]

Em Wed, Mar 08, 2023 at 02:59:07PM -0800, Ian Rogers escreveu:
> The computed name respects software events and aux event groups, such
> that the pmu_name is changed to be that of the aux event leader or
> group leader for software events. This is done as a later change will
> split events that are in different PMUs into different groups.

This makes 'perf test python' to fail:

⬢[acme@toolbox perf-tools-next]$ perf test -v python
Couldn't bump rlimit(MEMLOCK), failures may take place when creating BPF maps, etc
 19: 'import perf' in python                                         :
--- start ---
test child forked, pid 720242
python usage test: "echo "import sys ; sys.path.append('/tmp/build/perf-tools-next/python'); import perf" | '/usr/bin/python3' "
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ImportError: /tmp/build/perf-tools-next/python/perf.cpython-311-x86_64-linux-gnu.so: undefined symbol: evsel__is_aux_event
test child finished with -1
---- end ----
'import perf' in python: FAILED!
⬢[acme@toolbox perf-tools-next]$

So I added the following patch, please run 'perf test' and 'make -C
tools/perf build-test' before submitting patch series.

- Arnaldo

diff --git a/tools/perf/util/python.c b/tools/perf/util/python.c
index ab48ffbb644805df..be336f1b2b689602 100644
--- a/tools/perf/util/python.c
+++ b/tools/perf/util/python.c
@@ -93,6 +93,11 @@ int perf_pmu__scan_file(struct perf_pmu *pmu, const char *name, const char *fmt,
 	return EOF;
 }
 
+bool evsel__is_aux_event(const struct evsel *evsel __maybe_unused)
+{
+	return false;
+}
+
 /*
  * Add this one here not to drag util/metricgroup.c
  */
 
> Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
> ---
>  tools/perf/util/evsel.c | 24 ++++++++++++++++++++++++
>  tools/perf/util/evsel.h |  1 +
>  2 files changed, 25 insertions(+)
> 
> diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
> index 2dc2c24252bb..51d9650267d0 100644
> --- a/tools/perf/util/evsel.c
> +++ b/tools/perf/util/evsel.c
> @@ -821,6 +821,30 @@ const char *evsel__name(struct evsel *evsel)
>  	return "unknown";
>  }
>  
> +const char *evsel__group_pmu_name(const struct evsel *evsel)
> +{
> +	const struct evsel *leader;
> +
> +	/* If the pmu_name is set use it. pmu_name isn't set for CPU and software events. */
> +	if (evsel->pmu_name)
> +		return evsel->pmu_name;
> +	/*
> +	 * Software events may be in a group with other uncore PMU events. Use
> +	 * the pmu_name of the group leader to avoid breaking the software event
> +	 * out of the group.
> +	 *
> +	 * Aux event leaders, like intel_pt, expect a group with events from
> +	 * other PMUs, so substitute the AUX event's PMU in this case.
> +	 */
> +	leader  = evsel__leader(evsel);
> +	if ((evsel->core.attr.type == PERF_TYPE_SOFTWARE || evsel__is_aux_event(leader)) &&
> +	    leader->pmu_name) {
> +		return leader->pmu_name;
> +	}
> +
> +	return "cpu";
> +}
> +
>  const char *evsel__metric_id(const struct evsel *evsel)
>  {
>  	if (evsel->metric_id)
> diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
> index 676c499323e9..d26745ca6147 100644
> --- a/tools/perf/util/evsel.h
> +++ b/tools/perf/util/evsel.h
> @@ -280,6 +280,7 @@ int arch_evsel__hw_name(struct evsel *evsel, char *bf, size_t size);
>  
>  int __evsel__hw_cache_type_op_res_name(u8 type, u8 op, u8 result, char *bf, size_t size);
>  const char *evsel__name(struct evsel *evsel);
> +const char *evsel__group_pmu_name(const struct evsel *evsel);
>  const char *evsel__metric_id(const struct evsel *evsel);
>  
>  static inline bool evsel__is_tool(const struct evsel *evsel)
> -- 
> 2.40.0.rc0.216.gc4246ad0f0-goog
> 

-- 

- Arnaldo