[PATCH v2 2/8] perf test: Display number of active running tests

[Ian Rogers]

Before polling or sleeping to wait for a test to complete, print out
": Running (<num> active)" where the number of active tests is
determined by iterating over the tests and seeing which return false
for check_if_command_finished. The line erasing and printing out only
occur if the number of runnings tests changes to avoid the line
flickering excessively. Knowing tests are running allows a user to
know a test is running and in parallel mode how many of the tests are
waiting to complete. If color mode is disabled then avoid displaying
the "Running" message as deleting the line isn't reliable.

Tested-by: James Clark <james.clark@xxxxxxxxxx>
Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
---
 tools/perf/tests/builtin-test.c | 93 ++++++++++++++++++++++-----------
 tools/perf/util/color.h         |  1 +
 2 files changed, 63 insertions(+), 31 deletions(-)

diff --git a/tools/perf/tests/builtin-test.c b/tools/perf/tests/builtin-test.c
index 470a9709427d..bf03fb42420b 100644
--- a/tools/perf/tests/builtin-test.c
+++ b/tools/perf/tests/builtin-test.c
@@ -242,7 +242,10 @@ static int run_test_child(struct child_process *process)
 	return -err;
 }
 
-static int print_test_result(struct test_suite *t, int i, int subtest, int result, int width)
+#define TEST_RUNNING -3
+
+static int print_test_result(struct test_suite *t, int i, int subtest, int result, int width,
+			     int running)
 {
 	if (has_subtests(t)) {
 		int subw = width > 2 ? width - 2 : width;
@@ -252,6 +255,9 @@ static int print_test_result(struct test_suite *t, int i, int subtest, int resul
 		pr_info("%3d: %-*s:", i + 1, width, test_description(t, subtest));
 
 	switch (result) {
+	case TEST_RUNNING:
+		color_fprintf(stderr, PERF_COLOR_YELLOW, " Running (%d active)\n", running);
+		break;
 	case TEST_OK:
 		pr_info(" Ok\n");
 		break;
@@ -273,14 +279,17 @@ static int print_test_result(struct test_suite *t, int i, int subtest, int resul
 	return 0;
 }
 
-static int finish_test(struct child_test *child_test, int width)
+static int finish_test(struct child_test **child_tests, int running_test, int child_test_num,
+		       int width)
 {
+	struct child_test *child_test = child_tests[running_test];
 	struct test_suite *t = child_test->test;
 	int i = child_test->test_num;
 	int subi = child_test->subtest;
 	int err = child_test->process.err;
-	bool err_done = err <= 0;
+	bool err_done = false;
 	struct strbuf err_output = STRBUF_INIT;
+	int last_running = -1;
 	int ret;
 
 	/*
@@ -294,7 +303,7 @@ static int finish_test(struct child_test *child_test, int width)
 	 * Busy loop reading from the child's stdout/stderr that are set to be
 	 * non-blocking until EOF.
 	 */
-	if (!err_done)
+	if (err > 0)
 		fcntl(err, F_SETFL, O_NONBLOCK);
 	if (verbose > 1) {
 		if (has_subtests(t))
@@ -308,38 +317,60 @@ static int finish_test(struct child_test *child_test, int width)
 			  .events = POLLIN | POLLERR | POLLHUP | POLLNVAL,
 			},
 		};
-		char buf[512];
-		ssize_t len;
-
-		/* Poll to avoid excessive spinning, timeout set for 100ms. */
-		poll(pfds, ARRAY_SIZE(pfds), /*timeout=*/100);
-		if (!err_done && pfds[0].revents) {
-			errno = 0;
-			len = read(err, buf, sizeof(buf) - 1);
-
-			if (len <= 0) {
-				err_done = errno != EAGAIN;
-			} else {
-				buf[len] = '\0';
-				if (verbose > 1)
-					fprintf(stdout, "%s", buf);
-				else
+		if (perf_use_color_default) {
+			int running = 0;
+
+			for (int y = running_test; y < child_test_num; y++) {
+				if (check_if_command_finished(&child_tests[y]->process) == 0)
+					running++;
+			}
+			if (running != last_running) {
+				if (last_running != -1) {
+					/*
+					 * Erase "Running (.. active)" line
+					 * printed before poll/sleep.
+					 */
+					fprintf(debug_file(), PERF_COLOR_DELETE_LINE);
+				}
+				print_test_result(t, i, subi, TEST_RUNNING, width, running);
+				last_running = running;
+			}
+		}
+
+		err_done = true;
+		if (err <= 0) {
+			/* No child stderr to poll, sleep for 10ms for child to complete. */
+			usleep(10 * 1000);
+		} else {
+			/* Poll to avoid excessive spinning, timeout set for 100ms. */
+			poll(pfds, ARRAY_SIZE(pfds), /*timeout=*/100);
+			if (pfds[0].revents) {
+				char buf[512];
+				ssize_t len;
+
+				len = read(err, buf, sizeof(buf) - 1);
+
+				if (len > 0) {
+					err_done = false;
+					buf[len] = '\0';
 					strbuf_addstr(&err_output, buf);
+				}
 			}
 		}
+		if (err_done)
+			err_done = check_if_command_finished(&child_test->process);
+	}
+	if (perf_use_color_default && last_running != -1) {
+		/* Erase "Running (.. active)" line printed before poll/sleep. */
+		fprintf(debug_file(), PERF_COLOR_DELETE_LINE);
 	}
 	/* Clean up child process. */
 	ret = finish_command(&child_test->process);
-	if (verbose == 1 && ret == TEST_FAIL) {
-		/* Add header for test that was skipped above. */
-		if (has_subtests(t))
-			pr_info("%3d.%1d: %s:\n", i + 1, subi + 1, test_description(t, subi));
-		else
-			pr_info("%3d: %s:\n", i + 1, test_description(t, -1));
+	if (verbose > 1 || (verbose == 1 && ret == TEST_FAIL))
 		fprintf(stderr, "%s", err_output.buf);
-	}
+
 	strbuf_release(&err_output);
-	print_test_result(t, i, subi, ret, width);
+	print_test_result(t, i, subi, ret, width, /*running=*/0);
 	if (err > 0)
 		close(err);
 	return 0;
@@ -355,7 +386,7 @@ static int start_test(struct test_suite *test, int i, int subi, struct child_tes
 		pr_debug("--- start ---\n");
 		err = test_function(test, subi)(test, subi);
 		pr_debug("---- end ----\n");
-		print_test_result(test, i, subi, err, width);
+		print_test_result(test, i, subi, err, width, /*running=*/0);
 		return 0;
 	}
 
@@ -380,7 +411,7 @@ static int start_test(struct test_suite *test, int i, int subi, struct child_tes
 	err = start_command(&(*child)->process);
 	if (err || !sequential)
 		return  err;
-	return finish_test(*child, width);
+	return finish_test(child, /*running_test=*/0, /*child_test_num=*/1, width);
 }
 
 #define for_each_test(j, k, t)					\
@@ -465,7 +496,7 @@ static int __cmd_test(int argc, const char *argv[], struct intlist *skiplist)
 	}
 	for (i = 0; i < child_test_num; i++) {
 		if (!sequential) {
-			int ret  = finish_test(child_tests[i], width);
+			int ret  = finish_test(child_tests, i, child_test_num, width);
 
 			if (ret)
 				return ret;
diff --git a/tools/perf/util/color.h b/tools/perf/util/color.h
index 01f7bed21c9b..4b9f8d5d4439 100644
--- a/tools/perf/util/color.h
+++ b/tools/perf/util/color.h
@@ -22,6 +22,7 @@
 #define MIN_GREEN	0.5
 #define MIN_RED		5.0
 
+#define PERF_COLOR_DELETE_LINE	"\033[A\33[2K\r"
 /*
  * This variable stores the value of color.ui
  */
-- 
2.47.0.rc1.288.g06298d1525-goog