perf parse-events: Make add PMU verbose output clearer

On a CPU like skylakex an uncore_iio_0 PMU may alias with
uncore_iio_free_running_0. The latter PMU doesn't support fc_mask as a
parameter and so pmu_config_term fails. Typically parse_events_add_pmu
is called in a loop where if one alias succeeds errors are ignored,
however, if multiple errors occur parse_events__handle_error will
currently give a WARN_ONCE.

This change removes the WARN_ONCE in parse_events__handle_error and
makes it a pr_debug. It adds verbose messages to parse_events_add_pmu
warning that non-fatal errors may occur, while giving details on the pmu
and config terms for useful context. pmu_config_term is altered so the
failing term and pmu are present in the case of the 'unknown term' error
which makes spotting the free_running case more straightforward.

Before:

  $ perf --debug verbose=3 stat -M llc_misses.pcie_read sleep 1
  Using CPUID GenuineIntel-6-55-4
  metric expr unc_iio_data_req_of_cpu.mem_read.part0 + unc_iio_data_req_of_cpu.mem_read.part1 + unc_iio_data_req_of_cpu.mem_read.part2 + unc_iio_data_req_of_cpu.mem_read.part3 for LLC_MISSES.PCIE_READ
  found event unc_iio_data_req_of_cpu.mem_read.part0
  found event unc_iio_data_req_of_cpu.mem_read.part1
  found event unc_iio_data_req_of_cpu.mem_read.part2
  found event unc_iio_data_req_of_cpu.mem_read.part3
  metric expr unc_iio_data_req_of_cpu.mem_read.part0 + unc_iio_data_req_of_cpu.mem_read.part1 + unc_iio_data_req_of_cpu.mem_read.part2 + unc_iio_data_req_of_cpu.mem_read.part3 for LLC_MISSES.PCIE_READ
  found event unc_iio_data_req_of_cpu.mem_read.part0
  found event unc_iio_data_req_of_cpu.mem_read.part1
  found event unc_iio_data_req_of_cpu.mem_read.part2
  found event unc_iio_data_req_of_cpu.mem_read.part3
  adding {unc_iio_data_req_of_cpu.mem_read.part0,unc_iio_data_req_of_cpu.mem_read.part1,unc_iio_data_req_of_cpu.mem_read.part2,unc_iio_data_req_of_cpu.mem_read.part3}:W,{unc_iio_data_req_of_cpu.mem_read.part0,unc_iio_data_req_of_cpu.mem_read.part1,unc_iio_data_req_of_cpu.mem_read.part2,unc_iio_data_req_of_cpu.mem_read.part3}:W
  intel_pt default config: tsc,mtc,mtc_period=3,psb_period=3,pt,branch
  WARNING: multiple event parsing errors
  ...
  Invalid event/parameter 'fc_mask'
  ...

After:

  $ perf --debug verbose=3 stat -M llc_misses.pcie_read sleep 1
  Using CPUID GenuineIntel-6-55-4
  metric expr unc_iio_data_req_of_cpu.mem_read.part0 + unc_iio_data_req_of_cpu.mem_read.part1 + unc_iio_data_req_of_cpu.mem_read.part2 + unc_iio_data_req_of_cpu.mem_read.part3 for LLC_MISSES.PCIE_READ
  found event unc_iio_data_req_of_cpu.mem_read.part0
  found event unc_iio_data_req_of_cpu.mem_read.part1
  found event unc_iio_data_req_of_cpu.mem_read.part2
  found event unc_iio_data_req_of_cpu.mem_read.part3
  metric expr unc_iio_data_req_of_cpu.mem_read.part0 + unc_iio_data_req_of_cpu.mem_read.part1 + unc_iio_data_req_of_cpu.mem_read.part2 + unc_iio_data_req_of_cpu.mem_read.part3 for LLC_MISSES.PCIE_READ
  found event unc_iio_data_req_of_cpu.mem_read.part0
  found event unc_iio_data_req_of_cpu.mem_read.part1
  found event unc_iio_data_req_of_cpu.mem_read.part2
  found event unc_iio_data_req_of_cpu.mem_read.part3
  adding {unc_iio_data_req_of_cpu.mem_read.part0,unc_iio_data_req_of_cpu.mem_read.part1,unc_iio_data_req_of_cpu.mem_read.part2,unc_iio_data_req_of_cpu.mem_read.part3}:W,{unc_iio_data_req_of_cpu.mem_read.part0,unc_iio_data_req_of_cpu.mem_read.part1,unc_iio_data_req_of_cpu.mem_read.part2,unc_iio_data_req_of_cpu.mem_read.part3}:W
  intel_pt default config: tsc,mtc,mtc_period=3,psb_period=3,pt,branch
  Attempting to add event pmu 'uncore_iio_free_running_5' with 'unc_iio_data_req_of_cpu.mem_read.part0,' that may result in non-fatal errors
  After aliases, add event pmu 'uncore_iio_free_running_5' with 'fc_mask,ch_mask,umask,event,' that may result in non-fatal errors
  Attempting to add event pmu 'uncore_iio_free_running_3' with 'unc_iio_data_req_of_cpu.mem_read.part0,' that may result in non-fatal errors
  After aliases, add event pmu 'uncore_iio_free_running_3' with 'fc_mask,ch_mask,umask,event,' that may result in non-fatal errors
  Attempting to add event pmu 'uncore_iio_free_running_1' with 'unc_iio_data_req_of_cpu.mem_read.part0,' that may result in non-fatal errors
  After aliases, add event pmu 'uncore_iio_free_running_1' with 'fc_mask,ch_mask,umask,event,' that may result in non-fatal errors
  Multiple errors dropping message: unknown term 'fc_mask' for pmu 'uncore_iio_free_running_3' (valid terms: event,umask,config,config1,config2,name,period,percore)
  ...

  So before you see a 'WARNING: multiple event parsing errors' and
  'Invalid event/parameter'. After you see 'Attempting... that may result
  in non-fatal errors' then 'Multiple errors...' with details that
  'fc_mask' wasn't known to a free running counter. While not completely
  clean, this makes it clearer that an error hasn't really occurred.

v2. addresses review feedback from Jiri Olsa <jolsa@redhat.com>.

Signed-off-by: Ian Rogers <irogers@google.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: John Garry <john.garry@huawei.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lore.kernel.org/lkml/20200513220635.54700-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 21 insertions, 12 deletions

diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index 92bd7fafcce6..93fe72a9dc0b 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -1056,7 +1056,8 @@ error:
  * Setup one of config[12] attr members based on the
  * user input data - term parameter.
  */
-static int pmu_config_term(struct list_head *formats,
+static int pmu_config_term(const char *pmu_name,
+			   struct list_head *formats,
 			   struct perf_event_attr *attr,
 			   struct parse_events_term *term,
 			   struct list_head *head_terms,
@@ -1082,16 +1083,24 @@ static int pmu_config_term(struct list_head *formats,
 
 	format = pmu_find_format(formats, term->config);
 	if (!format) {
-		if (verbose > 0)
-			printf("Invalid event/parameter '%s'\n", term->config);
+		char *pmu_term = pmu_formats_string(formats);
+		char *unknown_term;
+		char *help_msg;
+
+		if (asprintf(&unknown_term,
+				"unknown term '%s' for pmu '%s'",
+				term->config, pmu_name) < 0)
+			unknown_term = NULL;
+		help_msg = parse_events_formats_error_string(pmu_term);
 		if (err) {
-			char *pmu_term = pmu_formats_string(formats);
-
 			parse_events__handle_error(err, term->err_term,
-				strdup("unknown term"),
-				parse_events_formats_error_string(pmu_term));
-			free(pmu_term);
+						   unknown_term,
+						   help_msg);
+		} else {
+			pr_debug("%s (%s)\n", unknown_term, help_msg);
+			free(unknown_term);
 		}
+		free(pmu_term);
 		return -EINVAL;
 	}
 
@@ -1168,7 +1177,7 @@ static int pmu_config_term(struct list_head *formats,
 	return 0;
 }
 
-int perf_pmu__config_terms(struct list_head *formats,
+int perf_pmu__config_terms(const char *pmu_name, struct list_head *formats,
 			   struct perf_event_attr *attr,
 			   struct list_head *head_terms,
 			   bool zero, struct parse_events_error *err)
@@ -1176,7 +1185,7 @@ int perf_pmu__config_terms(struct list_head *formats,
 	struct parse_events_term *term;
 
 	list_for_each_entry(term, head_terms, list) {
-		if (pmu_config_term(formats, attr, term, head_terms,
+		if (pmu_config_term(pmu_name, formats, attr, term, head_terms,
 				    zero, err))
 			return -EINVAL;
 	}
@@ -1196,8 +1205,8 @@ int perf_pmu__config(struct perf_pmu *pmu, struct perf_event_attr *attr,
 	bool zero = !!pmu->default_config;
 
 	attr->type = pmu->type;
-	return perf_pmu__config_terms(&pmu->format, attr, head_terms,
-				      zero, err);
+	return perf_pmu__config_terms(pmu->name, &pmu->format, attr,
+				      head_terms, zero, err);
 }
 
 static struct perf_pmu_alias *pmu_find_alias(struct perf_pmu *pmu,