From: Andi Kleen <ak@linux.intel.com>
Date: Wed, 13 May 2026 14:49:06 +0000 (-0700)
Subject: perf stat: Make metric only column line up with header
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7a978c2ac722d527852c0239ecc71108547c7a23;p=thirdparty%2Flinux.git

perf stat: Make metric only column line up with header

Since some time the metric-only output columns are messed up and do not
line up with the header, which makes it hard to read. I haven't bisected
it, but presumably it was broken for some time.

There were multiple problems:
- The dummy pm invocation at the beginning did print a bogus field
- The column computation in pm did not agree with the header length
- The color escape strings from highlighting confuse printf's field
  length computation

Fix all those. I simplified the column width computation significantly,
ignoring EVNAME_LEN, MGROUP_LEN, config->unit_width which don't
seem to be useful in the metric only context. It now only uses
the actual unit width as well as config->metric_only_len. The result
is more code removed than added.

Before:

% perf stat --topdown -a -I 1000
+           time %  tma_backend_bound %  tma_frontend_bound %  tma_bad_speculation      %  tma_retiring
     1.000190386                                         45.5                   40.0                     5.3                     9.2
     2.005185654                                         45.3                   40.1                     5.6                     9.0
     3.009193207                                         45.4                   39.9                     5.6                     9.1

After:

% perf stat --topdown -a -I 1000
+          time %  tma_backend_bound %  tma_frontend_bound %  tma_bad_speculation      %  tma_retiring
     1.000810024                 46.3                 39.7                   5.3                 8.7
     2.004800656                 45.8                 39.8                   5.4                 8.9
     3.008804783                 46.0                 39.6                   5.4                 9.0

Reviewed-by: Ian Rogers <irogers@google.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---

diff --git a/tools/perf/util/stat-display.c b/tools/perf/util/stat-display.c
index 993f4c4b8f442..2b69d238858cf 100644
--- a/tools/perf/util/stat-display.c
+++ b/tools/perf/util/stat-display.c
@@ -580,16 +580,13 @@ static void print_metricgroup_header_std(struct perf_stat_config *config,
 					 const char *metricgroup_name)
 {
 	struct outstate *os = ctx;
-	int n;
 
 	if (!metricgroup_name) {
 		__new_line_std(config, os);
 		return;
 	}
 
-	n = fprintf(config->output, " %*s", EVNAME_LEN, metricgroup_name);
-
-	fprintf(config->output, "%*s", MGROUP_LEN + config->unit_width + 2 - n, "");
+	fprintf(config->output, " %*s", config->metric_only_len, metricgroup_name);
 }
 
 static void print_metric_only(struct perf_stat_config *config,
@@ -599,19 +596,20 @@ static void print_metric_only(struct perf_stat_config *config,
 	struct outstate *os = ctx;
 	FILE *out = os->fh;
 	char str[1024];
-	unsigned mlen = config->metric_only_len;
+	unsigned mlen;
 	const char *color = metric_threshold_classify__color(thresh);
+	int olen;
 
-	if (!unit)
-		unit = "";
-	if (mlen < strlen(unit))
-		mlen = strlen(unit) + 1;
+	if (!unit) {
+		os->first = false;
+		return;
+	}
 
-	if (color)
-		mlen += strlen(color) + sizeof(PERF_COLOR_RESET) - 1;
+	mlen = max_t(unsigned, strlen(unit), config->metric_only_len);
 
+	olen = snprintf(str, sizeof(str), fmt ?: "", val);
 	color_snprintf(str, sizeof(str), color ?: "", fmt ?: "", val);
-	fprintf(out, "%*s ", mlen, str);
+	fprintf(out, "%*s%s", max_t(int, mlen - olen, 1), "", str);
 	os->first = false;
 }