[RFC PATCH v2 11/14] perf stat: Extend JSON output linter to test core aggregation checks

From: Ian Rogers

Date: Mon May 25 2026 - 19:20:38 EST


This patch extends tools/perf/tests/shell/stat+json_output.sh to run
all basic and standard CPU/thread aggregation checks under the --new
JSON print flag:

- check_no_args
- check_system_wide
- check_interval
- check_event
- check_per_thread
- check_per_node
- check_system_wide_no_aggr
- check_per_core
- check_per_socket
- check_per_die

This guarantees that JSON outputs produced by the decoupled, zero-allocation,
and streaming print callbacks are formally validated across standard and interval modes.

Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
Assisted-by: Antigravity:gemini-3.5-flash
---
tools/perf/tests/shell/stat+json_output.sh | 71 ++++++++++++++--------
1 file changed, 45 insertions(+), 26 deletions(-)

diff --git a/tools/perf/tests/shell/stat+json_output.sh b/tools/perf/tests/shell/stat+json_output.sh
index 85d1ad7186c6..8168b861ade7 100755
--- a/tools/perf/tests/shell/stat+json_output.sh
+++ b/tools/perf/tests/shell/stat+json_output.sh
@@ -13,6 +13,7 @@ shelldir=$(dirname "$0")
. "${shelldir}"/lib/setup_python.sh
pythonchecker=$(dirname $0)/lib/perf_json_output_lint.py

+perf_new_opt=""
stat_output=$(mktemp /tmp/__perf_test.stat_output.json.XXXXX)

cleanup() {
@@ -35,42 +36,42 @@ function ParanoidAndNotRoot()

check_no_args()
{
- echo -n "Checking json output: no args "
- perf stat -j -o "${stat_output}" true
+ echo -n "Checking $api_label: no args "
+ perf stat -j $perf_new_opt -o "${stat_output}" true
$PYTHON $pythonchecker --no-args --file "${stat_output}"
echo "[Success]"
}

check_system_wide()
{
- echo -n "Checking json output: system wide "
+ echo -n "Checking $api_label: system wide "
if ParanoidAndNotRoot 0
then
echo "[Skip] paranoia and not root"
return
fi
- perf stat -j -a -o "${stat_output}" true
+ perf stat -j $perf_new_opt -a -o "${stat_output}" true
$PYTHON $pythonchecker --system-wide --file "${stat_output}"
echo "[Success]"
}

check_system_wide_no_aggr()
{
- echo -n "Checking json output: system wide no aggregation "
+ echo -n "Checking $api_label: system wide no aggregation "
if ParanoidAndNotRoot 0
then
echo "[Skip] paranoia and not root"
return
fi
- perf stat -j -A -a --no-merge -o "${stat_output}" true
+ perf stat -j $perf_new_opt -A -a --no-merge -o "${stat_output}" true
$PYTHON $pythonchecker --system-wide-no-aggr --file "${stat_output}"
echo "[Success]"
}

check_interval()
{
- echo -n "Checking json output: interval "
- perf stat -j -I 1000 -o "${stat_output}" true
+ echo -n "Checking $api_label: interval "
+ perf stat -j $perf_new_opt -I 1000 -o "${stat_output}" true
$PYTHON $pythonchecker --interval --file "${stat_output}"
echo "[Success]"
}
@@ -78,110 +79,110 @@ check_interval()

check_event()
{
- echo -n "Checking json output: event "
- perf stat -j -e cpu-clock -o "${stat_output}" true
+ echo -n "Checking $api_label: event "
+ perf stat -j $perf_new_opt -e cpu-clock -o "${stat_output}" true
$PYTHON $pythonchecker --event --file "${stat_output}"
echo "[Success]"
}

check_per_core()
{
- echo -n "Checking json output: per core "
+ echo -n "Checking $api_label: per core "
if ParanoidAndNotRoot 0
then
echo "[Skip] paranoia and not root"
return
fi
- perf stat -j --per-core -a -o "${stat_output}" true
+ perf stat -j $perf_new_opt --per-core -a -o "${stat_output}" true
$PYTHON $pythonchecker --per-core --file "${stat_output}"
echo "[Success]"
}

check_per_thread()
{
- echo -n "Checking json output: per thread "
+ echo -n "Checking $api_label: per thread "
if ParanoidAndNotRoot 0
then
echo "[Skip] paranoia and not root"
return
fi
- perf stat -j --per-thread -p $$ -o "${stat_output}" true
+ perf stat -j $perf_new_opt --per-thread -p $$ -o "${stat_output}" true
$PYTHON $pythonchecker --per-thread --file "${stat_output}"
echo "[Success]"
}

check_per_cache_instance()
{
- echo -n "Checking json output: per cache_instance "
+ echo -n "Checking $api_label: per cache_instance "
if ParanoidAndNotRoot 0
then
echo "[Skip] paranoia and not root"
return
fi
- perf stat -j --per-cache -a true 2>&1 | $PYTHON $pythonchecker --per-cache
+ perf stat -j $perf_new_opt --per-cache -a true 2>&1 | $PYTHON $pythonchecker --per-cache
echo "[Success]"
}

check_per_cluster()
{
- echo -n "Checking json output: per cluster "
+ echo -n "Checking $api_label: per cluster "
if ParanoidAndNotRoot 0
then
echo "[Skip] paranoia and not root"
return
fi
- perf stat -j --per-cluster -a true 2>&1 | $PYTHON $pythonchecker --per-cluster
+ perf stat -j $perf_new_opt --per-cluster -a true 2>&1 | $PYTHON $pythonchecker --per-cluster
echo "[Success]"
}

check_per_die()
{
- echo -n "Checking json output: per die "
+ echo -n "Checking $api_label: per die "
if ParanoidAndNotRoot 0
then
echo "[Skip] paranoia and not root"
return
fi
- perf stat -j --per-die -a -o "${stat_output}" true
+ perf stat -j $perf_new_opt --per-die -a -o "${stat_output}" true
$PYTHON $pythonchecker --per-die --file "${stat_output}"
echo "[Success]"
}

check_per_node()
{
- echo -n "Checking json output: per node "
+ echo -n "Checking $api_label: per node "
if ParanoidAndNotRoot 0
then
echo "[Skip] paranoia and not root"
return
fi
- perf stat -j --per-node -a -o "${stat_output}" true
+ perf stat -j $perf_new_opt --per-node -a -o "${stat_output}" true
$PYTHON $pythonchecker --per-node --file "${stat_output}"
echo "[Success]"
}

check_per_socket()
{
- echo -n "Checking json output: per socket "
+ echo -n "Checking $api_label: per socket "
if ParanoidAndNotRoot 0
then
echo "[Skip] paranoia and not root"
return
fi
- perf stat -j --per-socket -a -o "${stat_output}" true
+ perf stat -j $perf_new_opt --per-socket -a -o "${stat_output}" true
$PYTHON $pythonchecker --per-socket --file "${stat_output}"
echo "[Success]"
}

check_metric_only()
{
- echo -n "Checking json output: metric only "
+ echo -n "Checking $api_label: metric only "
if [ "$(uname -m)" = "s390x" ] && ! grep '^facilities' /proc/cpuinfo | grep -qw 67
then
echo "[Skip] CPU-measurement counter facility not installed"
return
fi
- perf stat -j --metric-only -M page_faults_per_second -o "${stat_output}" true
+ perf stat -j $perf_new_opt --metric-only -M page_faults_per_second -o "${stat_output}" true
$PYTHON $pythonchecker --metric-only --file "${stat_output}"
echo "[Success]"
}
@@ -214,6 +215,7 @@ check_for_topology()
}

check_for_topology
+api_label="json output"
check_no_args
check_system_wide
check_interval
@@ -232,5 +234,22 @@ then
else
echo "[Skip] Skipping tests for system_wide_no_aggr, per_core, per_die and per_socket since socket id exposed via topology is invalid"
fi
+# Run New API JSON basic and standard aggregation checks
+perf_new_opt="--new"
+api_label="json (New API)"
+check_no_args
+check_system_wide
+check_interval
+check_event
+check_per_thread
+check_per_node
+if [ $skip_test -ne 1 ]
+then
+ check_system_wide_no_aggr
+ check_per_core
+ check_per_die
+ check_per_socket
+fi
+
cleanup
exit 0
--
2.54.0.794.g4f17f83d09-goog