[nrf fromlist] tests: kernel: usage: thread_runtime_stats: Improve test_all_stats_usage

Improve robustness of test_all_stats_usage test. Test was relying on a
fact that system did not go to idle before this test is run. It means
that it was assuming that it will be the first test which might not be
true. Additionally, on some targets there might be some idle waits
during system boot. Test is adjusted to validate gathered statistics
with an assumption that there might have been idle period prior to the
test.

Upstream PR #: 86139

Signed-off-by: Krzysztof Chruściński <[email protected]>

Author: nordic-krch

tests/kernel/usage/thread_runtime_stats/src/test_thread_runtime_stats.c

@@ -100,16 +100,16 @@ ZTEST(usage_api, test_all_stats_usage)
 
 	/*
 	 * Verify that before the system idles for 2 ticks that
-	 * [execution_cycles] is increasing, [total_cycles] matches
+	 * [execution_cycles] is increasing, [total_cycles + idle_cycles] matches
 	 * [execution_cycles] and [idle_cycles] is not changing (as the
-	 * system has been idle yet.
+	 * system is not going to idle during that test).
 	 */
 
 	zassert_true(stats2.execution_cycles > stats1.execution_cycles);
 	zassert_true(stats3.execution_cycles > stats2.execution_cycles);
-	zassert_true(stats1.execution_cycles == stats1.total_cycles);
-	zassert_true(stats2.execution_cycles == stats2.total_cycles);
-	zassert_true(stats3.execution_cycles == stats3.total_cycles);
+	zassert_true(stats1.execution_cycles == (stats1.total_cycles + stats1.idle_cycles));
+	zassert_true(stats2.execution_cycles == (stats2.total_cycles + stats2.idle_cycles));
+	zassert_true(stats3.execution_cycles == (stats3.total_cycles + stats3.idle_cycles));
 #ifdef CONFIG_SCHED_THREAD_USAGE_ALL
 	zassert_true(stats1.idle_cycles == stats2.idle_cycles);
 	zassert_true(stats1.idle_cycles == stats3.idle_cycles);
@@ -122,8 +122,8 @@ ZTEST(usage_api, test_all_stats_usage)
 	 * going idle.
 	 * 1. [current_cycles] increases.
 	 * 2. [peak_cycles] matches [current_cycles].
-	 * 3. [average_cycles] is 0 (because system has not gone idle yet)
-	 * 4. [current_cycles] matches [execution_cycles].
+	 * 3. [average_cycles] is 0 if system has not gone idle yet
+	 * 4. [current_cycles] matches [execution_cycles] if system has not gone idle yet
 	 */
 
 	zassert_true(stats2.current_cycles > stats1.current_cycles);
@@ -133,13 +133,19 @@ ZTEST(usage_api, test_all_stats_usage)
 	zassert_true(stats2.peak_cycles == stats2.current_cycles);
 	zassert_true(stats3.peak_cycles == stats3.current_cycles);
 
-	zassert_true(stats1.average_cycles == 0);
-	zassert_true(stats2.average_cycles == 0);
-	zassert_true(stats3.average_cycles == 0);
-
-	zassert_true(stats1.current_cycles == stats1.execution_cycles);
-	zassert_true(stats2.current_cycles == stats2.execution_cycles);
-	zassert_true(stats3.current_cycles == stats3.execution_cycles);
+	if (stats1.idle_cycles == 0) {
+		zassert_true(stats1.average_cycles == 0);
+		zassert_true(stats2.average_cycles == 0);
+		zassert_true(stats3.average_cycles == 0);
+
+		zassert_true(stats1.current_cycles == stats1.execution_cycles);
+		zassert_true(stats2.current_cycles == stats2.execution_cycles);
+		zassert_true(stats3.current_cycles == stats3.execution_cycles);
+	} else {
+		zassert_true(stats1.current_cycles < stats1.execution_cycles);
+		zassert_true(stats2.current_cycles < stats2.execution_cycles);
+		zassert_true(stats3.current_cycles < stats3.execution_cycles);
+	}
 #endif
 
 	/*
@@ -172,7 +178,7 @@ ZTEST(usage_api, test_all_stats_usage)
 					   stats3.peak_cycles, IDLE_EVENT_STATS_PRECISION), NULL);
 	zassert_true(stats4.peak_cycles == stats5.peak_cycles);
 
-	zassert_true(stats4.average_cycles > stats3.average_cycles);
+	zassert_true(stats4.average_cycles > 0);
 	zassert_true(stats5.average_cycles > stats4.average_cycles);
 #endif