[PATCH v2 3/3] perf metricgroup: Refine error logs

[Leo Yan]

Return -ENOENT when no metric/group matches, and directly use the return
value from expr__find_ids(), so -EINVAL is reserved for parse failures.

Print separate logs to make it clear.

Before:

  perf stat -C 5 -vvv
  Using CPUID 0x00000000410fd490
  metric expr 100 * (STALL_SLOT_BACKEND / (CPU_CYCLES * #slots) - BR_MIS_PRED * 3 / CPU_CYCLES) for backend_bound
  parsing metric: 100 * (STALL_SLOT_BACKEND / (CPU_CYCLES * #slots) - BR_MIS_PRED * 3 / CPU_CYCLES)
  Failure to read '#slots'
  literal: #slots = nan
  syntax error
  Cannot find metric or group `Default'

After:

  perf stat -C 5 -vvv
  Using CPUID 0x00000000410fd490
  metric expr 100 * (STALL_SLOT_BACKEND / (CPU_CYCLES * #slots) - BR_MIS_PRED * 3 / CPU_CYCLES) for backend_bound
  parsing metric: 100 * (STALL_SLOT_BACKEND / (CPU_CYCLES * #slots) - BR_MIS_PRED * 3 / CPU_CYCLES)
  Failure to read '#slots'
  literal: #slots = nan
  syntax error
  Fail to parse metric or group `Default'

Signed-off-by: Leo Yan <leo.yan@xxxxxxx>
---
 tools/perf/util/metricgroup.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/tools/perf/util/metricgroup.c b/tools/perf/util/metricgroup.c
index f7d53b4e46f45cb01181a462cb5bb5ca5a3b1a9c..4db9578efd811cf91d192cc13fb757cf5aab21f7 100644
--- a/tools/perf/util/metricgroup.c
+++ b/tools/perf/util/metricgroup.c
@@ -914,10 +914,9 @@ static int __add_metric(struct list_head *metric_list,
 		expr = metric_no_threshold ? pm->metric_name : pm->metric_threshold;
 		visited_node.name = "__threshold__";
 	}
-	if (expr__find_ids(expr, NULL, root_metric->pctx) < 0) {
-		/* Broken metric. */
-		ret = -EINVAL;
-	}
+
+	ret = expr__find_ids(expr, NULL, root_metric->pctx);
+
 	if (!ret) {
 		/* Resolve referenced metrics. */
 		struct perf_pmu *pmu;
@@ -1101,7 +1100,7 @@ static int metricgroup__add_metric(const char *pmu, const char *metric_name, con
 	 */
 	ret = metricgroup__for_each_metric(table, metricgroup__add_metric_callback, &data);
 	if (!ret && !data.has_match)
-		ret = -EINVAL;
+		ret = -ENOENT;
 
 	/*
 	 * add to metric_list so that they can be released
@@ -1152,6 +1151,8 @@ static int metricgroup__add_metric_list(const char *pmu, const char *list,
 					      user_requested_cpu_list,
 					      system_wide, metric_list, table);
 		if (ret == -EINVAL)
+			pr_err("Fail to parse metric or group `%s'\n", metric_name);
+		else if (ret == -ENOENT)
 			pr_err("Cannot find metric or group `%s'\n", metric_name);
 
 		if (ret)

-- 
2.34.1