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.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/arch/x86/util/intel-pt.c

@@ -59,7 +59,8 @@ struct intel_pt_recording {
 	size_t				priv_size;
 };
 
-static int intel_pt_parse_terms_with_default(struct list_head *formats,
+static int intel_pt_parse_terms_with_default(const char *pmu_name,
+					     struct list_head *formats,
 					     const char *str,
 					     u64 *config)
 {
@@ -78,7 +79,8 @@ static int intel_pt_parse_terms_with_default(struct list_head *formats,
 		goto out_free;
 
 	attr.config = *config;
-	err = perf_pmu__config_terms(formats, &attr, terms, true, NULL);
+	err = perf_pmu__config_terms(pmu_name, formats, &attr, terms, true,
+				     NULL);
 	if (err)
 		goto out_free;
 
@@ -88,11 +90,12 @@ static int intel_pt_parse_terms_with_default(struct list_head *formats,
 	return err;
 }
 
-static int intel_pt_parse_terms(struct list_head *formats, const char *str,
-				u64 *config)
+static int intel_pt_parse_terms(const char *pmu_name, struct list_head *formats,
+				const char *str, u64 *config)
 {
 	*config = 0;
-	return intel_pt_parse_terms_with_default(formats, str, config);
+	return intel_pt_parse_terms_with_default(pmu_name, formats, str,
+						 config);
 }
 
 static u64 intel_pt_masked_bits(u64 mask, u64 bits)
@@ -229,7 +232,8 @@ static u64 intel_pt_default_config(struct perf_pmu *intel_pt_pmu)
 
 	pr_debug2("%s default config: %s\n", intel_pt_pmu->name, buf);
 
-	intel_pt_parse_terms(&intel_pt_pmu->format, buf, &config);
+	intel_pt_parse_terms(intel_pt_pmu->name, &intel_pt_pmu->format, buf,
+			     &config);
 
 	return config;
 }
@@ -337,13 +341,16 @@ static int intel_pt_info_fill(struct auxtrace_record *itr,
 	if (priv_size != ptr->priv_size)
 		return -EINVAL;
 
-	intel_pt_parse_terms(&intel_pt_pmu->format, "tsc", &tsc_bit);
-	intel_pt_parse_terms(&intel_pt_pmu->format, "noretcomp",
-			     &noretcomp_bit);
-	intel_pt_parse_terms(&intel_pt_pmu->format, "mtc", &mtc_bit);
+	intel_pt_parse_terms(intel_pt_pmu->name, &intel_pt_pmu->format,
+			     "tsc", &tsc_bit);
+	intel_pt_parse_terms(intel_pt_pmu->name, &intel_pt_pmu->format,
+			     "noretcomp", &noretcomp_bit);
+	intel_pt_parse_terms(intel_pt_pmu->name, &intel_pt_pmu->format,
+			     "mtc", &mtc_bit);
 	mtc_freq_bits = perf_pmu__format_bits(&intel_pt_pmu->format,
 					      "mtc_period");
-	intel_pt_parse_terms(&intel_pt_pmu->format, "cyc", &cyc_bit);
+	intel_pt_parse_terms(intel_pt_pmu->name, &intel_pt_pmu->format,
+			     "cyc", &cyc_bit);
 
 	intel_pt_tsc_ctc_ratio(&tsc_ctc_ratio_n, &tsc_ctc_ratio_d);
 
@@ -768,7 +775,8 @@ static int intel_pt_recording_options(struct auxtrace_record *itr,
 		}
 	}
 
-	intel_pt_parse_terms(&intel_pt_pmu->format, "tsc", &tsc_bit);
+	intel_pt_parse_terms(intel_pt_pmu->name, &intel_pt_pmu->format,
+			     "tsc", &tsc_bit);
 
 	if (opts->full_auxtrace && (intel_pt_evsel->core.attr.config & tsc_bit))
 		have_timing_info = true;

tools/perf/tests/pmu.c

@@ -156,8 +156,8 @@ int test__pmu(struct test *test __maybe_unused, int subtest __maybe_unused)
 		if (ret)
 			break;
 
-		ret = perf_pmu__config_terms(&formats, &attr, terms,
-					     false, NULL);
+		ret = perf_pmu__config_terms("perf-pmu-test", &formats, &attr,
+					     terms, false, NULL);
 		if (ret)
 			break;
 

tools/perf/util/parse-events.c

@@ -204,7 +204,8 @@ void parse_events__handle_error(struct parse_events_error *err, int idx,
 		err->help = help;
 		break;
 	default:
-		WARN_ONCE(1, "WARNING: multiple event parsing errors\n");
+		pr_debug("Multiple errors dropping message: %s (%s)\n",
+			err->str, err->help);
 		free(err->str);
 		err->str = str;
 		free(err->help);
@@ -1422,6 +1423,19 @@ int parse_events_add_pmu(struct parse_events_state *parse_state,
 	bool use_uncore_alias;
 	LIST_HEAD(config_terms);
 
+	if (verbose > 1) {
+		fprintf(stderr, "Attempting to add event pmu '%s' with '",
+			name);
+		if (head_config) {
+			struct parse_events_term *term;
+
+			list_for_each_entry(term, head_config, list) {
+				fprintf(stderr, "%s,", term->config);
+			}
+		}
+		fprintf(stderr, "' that may result in non-fatal errors\n");
+	}
+
 	pmu = perf_pmu__find(name);
 	if (!pmu) {
 		char *err_str;
@@ -1458,6 +1472,19 @@ int parse_events_add_pmu(struct parse_events_state *parse_state,
 	if (perf_pmu__check_alias(pmu, head_config, &info))
 		return -EINVAL;
 
+	if (verbose > 1) {
+		fprintf(stderr, "After aliases, add event pmu '%s' with '",
+			name);
+		if (head_config) {
+			struct parse_events_term *term;
+
+			list_for_each_entry(term, head_config, list) {
+				fprintf(stderr, "%s,", term->config);
+			}
+		}
+		fprintf(stderr, "' that may result in non-fatal errors\n");
+	}
+
 	/*
 	 * Configure hardcoded terms first, no need to check
 	 * return value when called with fail == 0 ;)

tools/perf/util/pmu.c

@@ -1056,7 +1056,8 @@ static char *pmu_formats_string(struct list_head *formats)
  * 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);
-		if (err) {
 		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) {
 			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,

tools/perf/util/pmu.h

@@ -76,7 +76,7 @@ struct perf_pmu *perf_pmu__find_by_type(unsigned int type);
 int perf_pmu__config(struct perf_pmu *pmu, struct perf_event_attr *attr,
 		     struct list_head *head_terms,
 		     struct parse_events_error *error);
-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 *error);