When running tests in parallel, the parent process reads output from the
child's pipe. However, it might exit the loop as soon as the child is
detected as finished, potentially missing data that arrived in the pipe
just after the last poll or before the loop terminated.
Address this by draining the pipe after the main loop in finish_test.
Assisted-by: Gemini-CLI:Google Gemini 3
Signed-off-by: Ian Rogers <irogers@google.com>
---
tools/perf/tests/builtin-test.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/tools/perf/tests/builtin-test.c b/tools/perf/tests/builtin-test.c
index f2c135891477..7946878195b7 100644
--- a/tools/perf/tests/builtin-test.c
+++ b/tools/perf/tests/builtin-test.c
@@ -483,6 +483,16 @@ static void finish_test(struct child_test **child_tests, int running_test, int c
if (err_done)
err_done = check_if_command_finished(&child_test->process);
}
+ /* Drain any remaining data from the pipe. */
+ if (err > 0) {
+ char buf[512];
+ ssize_t len;
+
+ while ((len = read(err, buf, sizeof(buf) - 1)) > 0) {
+ buf[len] = '\0';
+ strbuf_addstr(&err_output, buf);
+ }
+ }
if (perf_use_color_default && last_running != -1) {
/* Erase "Running (.. active)" line printed before poll/sleep. */
fprintf(debug_file(), PERF_COLOR_DELETE_LINE);
--
2.54.0.929.g9b7fa37559-goog