[PATCH 2/2] perf stat: Also hide metric from JSON if units are an empty string
From: James Clark
Date: Fri Oct 25 2024 - 05:05:19 EST
We decided to hide NULL metric units rather than showing it as "(null)",
but on hybrid systems if the process doesn't hit a PMU you get an empty
string metric unit instead. To make it consistent also remove empty
strings.
Note that metric-threshold is already hidden in this case without this
change.
Where a process only runs on cpu_core and never hits cpu_atom:
Before:
$ perf stat -j -- true
...
{"counter-value" : "<not counted>", "unit" : "", "event" : "cpu_atom/branch-misses/", "event-runtime" : 0, "pcnt-running" : 0.00, "metric-value" : "0.000000", "metric-unit" : ""}
{"counter-value" : "6326.000000", "unit" : "", "event" : "cpu_core/branch-misses/", "event-runtime" : 293786, "pcnt-running" : 100.00, "metric-value" : "3.553394", "metric-unit" : "of all branches", "metric-threshold" : "good"}
...
After:
...
{"counter-value" : "<not counted>", "unit" : "", "event" : "cpu_atom/branch-misses/", "event-runtime" : 0, "pcnt-running" : 0.00}
{"counter-value" : "5778.000000", "unit" : "", "event" : "cpu_core/branch-misses/", "event-runtime" : 282240, "pcnt-running" : 100.00, "metric-value" : "3.226797", "metric-unit" : "of all branches", "metric-threshold" : "good"}
...
Signed-off-by: James Clark <james.clark@xxxxxxxxxx>
---
tools/perf/util/stat-display.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/perf/util/stat-display.c b/tools/perf/util/stat-display.c
index a5d72f4a515c..9b7fd985a42a 100644
--- a/tools/perf/util/stat-display.c
+++ b/tools/perf/util/stat-display.c
@@ -506,7 +506,7 @@ static void print_metric_json(struct perf_stat_config *config __maybe_unused,
struct outstate *os = ctx;
FILE *out = os->fh;
- if (unit) {
+ if (unit && strlen(unit)) {
json_out(os, "\"metric-value\" : \"%f\", \"metric-unit\" : \"%s\"", val, unit);
if (thresh != METRIC_THRESHOLD_UNKNOWN) {
json_out(os, "\"metric-threshold\" : \"%s\"",
--
2.34.1