validation: time: relax global time sync tolerance with 1 CPU

When running the 2-thread time_test_global_sync_control() test in a system
with only one CPU core, the control and worker threads run in the same
core, which shows up as time differences of the order of the thread
scheduling interval of the underlying OS. Increase the allowed error when
the threads run in the same CPU core.

Signed-off-by: Janne Peltonen <[email protected]>
Reviewed-by: Matias Elo <[email protected]>

test/validation/api/time/time.c

@@ -1,5 +1,5 @@
 /* Copyright (c) 2015-2018, Linaro Limited
- * Copyright (c) 2019-2023, Nokia
+ * Copyright (c) 2019-2024, Nokia
  * All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
@@ -24,6 +24,7 @@
 #define TIME_SAMPLES		2
 #define TIME_TOLERANCE_NS	1000000
 #define TIME_TOLERANCE_CI_NS	40000000
+#define TIME_TOLERANCE_1CPU_NS	40000000
 #define GLOBAL_SHM_NAME		"GlobalTimeTest"
 #define YEAR_IN_NS              (365 * 24 * ODP_TIME_HOUR_IN_NS)
 
@@ -858,8 +859,7 @@ static void time_test_global_sync(const int ctrl)
 	odph_thread_common_param_t thr_common;
 	odph_thread_param_t thr_param;
 	odph_thread_t thread_tbl[MAX_WORKERS];
-	const uint64_t tolerance =
-		odp_cunit_ci() ? TIME_TOLERANCE_CI_NS : TIME_TOLERANCE_NS;
+	uint64_t tolerance = odp_cunit_ci() ? TIME_TOLERANCE_CI_NS : TIME_TOLERANCE_NS;
 	const int num = ctrl ? 2 : global_mem->num_threads;
 
 	if (num < 2) {
@@ -879,14 +879,23 @@ static void time_test_global_sync(const int ctrl)
 
 	if (ctrl) {
 		/* Test sync between one control and one worker thread. */
+		int control_cpu;
+		int worker_cpu;
+
 		odp_cpumask_default_control(&cpumask, 1);
 		thr_common.cpumask = &cpumask;
 		thr_param.thr_type = ODP_THREAD_CONTROL;
+		control_cpu = odp_cpumask_first(&cpumask);
 
 		int r = odph_thread_create(&thread_tbl[thr++],
 					   &thr_common, &thr_param, 1);
 		CU_ASSERT_FATAL(r == 1);
 		odp_cpumask_default_worker(&cpumask, 1);
+		worker_cpu = odp_cpumask_first(&cpumask);
+		if (control_cpu == worker_cpu) {
+			printf(" single CPU, relaxing tolerance. ");
+			tolerance = TIME_TOLERANCE_1CPU_NS;
+		}
 	} else {
 		/* Test sync between num worker threads. */
 		odp_cpumask_default_worker(&cpumask, num);