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, 28 insertions, 1 deletions

diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index e37a6a3e6217..6434db2e10dd 100644
--- a/tools/perf/util/parse-events.c
+++ b/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 ;)