When running perf test, the status column (: Ok) became misaligned when
subtest indexes reached 2 or 3 digits (e.g. 9.100 vs 9.9 vs 10.1). This
occurred because the subtest description field width (subw) was
statically fixed to width - 2, assuming all subtest index prefixes were
exactly 7 characters wide.

Dynamically calculate subw based on the exact character length of the
test suite and subtest index prefix. This ensures the status column is
perfectly aligned vertically across all test outputs regardless of
subtest index digit count.

Assisted-by: Gemini-CLI:Google Gemini 3
Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/tests/builtin-test.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/tools/perf/tests/builtin-test.c b/tools/perf/tests/builtin-test.c
index f6bb876a271d..486f563ec04f 100644
--- a/tools/perf/tests/builtin-test.c
+++ b/tools/perf/tests/builtin-test.c
@@ -376,10 +376,12 @@ static int print_test_result(struct test_suite *t, int curr_suite, int curr_test
 			     int result, int width, int running)
 {
 	if (test_suite__num_test_cases(t) > 1) {
-		int subw = width > 2 ? width - 2 : width;
+		char prefix[32];
+		int len = snprintf(prefix, sizeof(prefix), "%3d.%1d:",
+				   curr_suite + 1, curr_test_case + 1);
+		int subw = len >= 4 ? width + 4 - len : width;
 
-		pr_info("%3d.%1d: %-*s:", curr_suite + 1, curr_test_case + 1, subw,
-			test_description(t, curr_test_case));
+		pr_info("%s %-*s:", prefix, subw, test_description(t, curr_test_case));
 	} else
 		pr_info("%3d: %-*s:", curr_suite + 1, width, test_description(t, curr_test_case));
 
-- 
2.54.0.929.g9b7fa37559-goog