[PATCH v2 0/4] Test fixes and debug logging

[PATCH v2 0/4] Test fixes and debug logging

[Ian Rogers]

Testing in a hypervisor guest showed some issues that these patches
try to address, or improve the debug situation upon.

v2: Rebase. Tested Arnaldo repeat case on Intel but didn't repro,
    assume was fixed as part of the legacy metric json test fixes.

v1: https://lore.kernel.org/lkml/20250914182900.1960567-1-irogers@google.com/

Ian Rogers (4):
  perf test: Be tolerant of missing json metric none value
  perf parse-events: Add debug logging to perf_event
  perf test: Don't fail if user rdpmc returns 0 when disabled
  perf stat: Display metric-only for 0 counters

 tools/perf/tests/mmap-basic.c                       | 2 +-
 tools/perf/tests/shell/lib/perf_json_output_lint.py | 5 ++++-
 tools/perf/util/parse-events.c                      | 2 ++
 tools/perf/util/stat-display.c                      | 3 +++
 4 files changed, 10 insertions(+), 2 deletions(-)

-- 
2.51.2.1041.gc1ab5b90ca-goog

[PATCH v2 1/4] perf test: Be tolerant of missing json metric none value

[Ian Rogers]

print_metric_only_json and print_metric_end in stat-display.c may
create a metric value of "none" which fails validation as isfloat. Add
a helper to properly validate metric numeric values.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/tests/shell/lib/perf_json_output_lint.py | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/tools/perf/tests/shell/lib/perf_json_output_lint.py b/tools/perf/tests/shell/lib/perf_json_output_lint.py
index 1369baaa0361..dafbde56cc76 100644
--- a/tools/perf/tests/shell/lib/perf_json_output_lint.py
+++ b/tools/perf/tests/shell/lib/perf_json_output_lint.py
@@ -43,6 +43,9 @@ def isint(num):
 def is_counter_value(num):
   return isfloat(num) or num == '<not counted>' or num == '<not supported>'
 
+def is_metric_value(num):
+  return isfloat(num) or num == 'none'
+
 def check_json_output(expected_items):
   checks = {
       'counters': lambda x: isfloat(x),
@@ -57,7 +60,7 @@ def check_json_output(expected_items):
       'event-runtime': lambda x: isfloat(x),
       'interval': lambda x: isfloat(x),
       'metric-unit': lambda x: True,
-      'metric-value': lambda x: isfloat(x),
+      'metric-value': lambda x: is_metric_value(x),
       'metric-threshold': lambda x: x in ['unknown', 'good', 'less good', 'nearly bad', 'bad'],
       'metricgroup': lambda x: True,
       'node': lambda x: True,
-- 
2.51.2.1041.gc1ab5b90ca-goog

[PATCH v2 2/4] perf parse-events: Add debug logging to perf_event

[Ian Rogers]

If verbose is enabled and parse_event is called, typically by tests,
log failures.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/util/parse-events.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index 0c0dc20b1c13..e522082c5a21 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -2236,6 +2236,8 @@ int parse_event(struct evlist *evlist, const char *str)
 
 	parse_events_error__init(&err);
 	ret = parse_events(evlist, str, &err);
+	if (ret && verbose > 0)
+		parse_events_error__print(&err, str);
 	parse_events_error__exit(&err);
 	return ret;
 }
-- 
2.51.2.1041.gc1ab5b90ca-goog

[PATCH v2 3/4] perf test: Don't fail if user rdpmc returns 0 when disabled

[Ian Rogers]

In certain hypervisor set ups the value 0 may be returned but this is
only erroneous if the user rdpmc isn't disabled.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/tests/mmap-basic.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/tests/mmap-basic.c b/tools/perf/tests/mmap-basic.c
index 3c89d3001887..3313c236104e 100644
--- a/tools/perf/tests/mmap-basic.c
+++ b/tools/perf/tests/mmap-basic.c
@@ -322,7 +322,7 @@ static int test_stat_user_read(u64 event, enum user_read_state enabled)
 		}
 
 		perf_evsel__read(evsel, 0, 0, &counts);
-		if (counts.val == 0) {
+		if (rdpmc_supported && counts.val == 0) {
 			pr_err("User space counter reading for PMU %s [Failed read]\n", pmu->name);
 			ret = TEST_FAIL;
 			goto cleanup;
-- 
2.51.2.1041.gc1ab5b90ca-goog

[PATCH v2 4/4] perf stat: Display metric-only for 0 counters

[Ian Rogers]

0 counters may occur in hypervisor settings but metric-only output is
always expected. This resolves an issue in the "perf stat STD output
linter" test.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/util/stat-display.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/tools/perf/util/stat-display.c b/tools/perf/util/stat-display.c
index 5ac9854f8c58..6d02f84c5691 100644
--- a/tools/perf/util/stat-display.c
+++ b/tools/perf/util/stat-display.c
@@ -913,6 +913,9 @@ static bool should_skip_zero_counter(struct perf_stat_config *config,
 	if (verbose == 0 && counter->skippable && !counter->supported)
 		return true;
 
+	/* Metric only counts won't be displayed but the metric wants to be computed. */
+	if (config->metric_only)
+		return false;
 	/*
 	 * Skip value 0 when enabling --per-thread globally,
 	 * otherwise it will have too many 0 output.
-- 
2.51.2.1041.gc1ab5b90ca-goog

Re: [PATCH v2 0/4] Test fixes and debug logging

[Namhyung Kim]

On Wed, 12 Nov 2025 11:53:07 -0800, Ian Rogers wrote:
> Testing in a hypervisor guest showed some issues that these patches
> try to address, or improve the debug situation upon.
> 
> v2: Rebase. Tested Arnaldo repeat case on Intel but didn't repro,
>     assume was fixed as part of the legacy metric json test fixes.
> 
> v1: https://lore.kernel.org/lkml/20250914182900.1960567-1-irogers@google.com/
> 
> [...]
Applied to perf-tools-next, thanks!

Best regards,
Namhyung