tests: Add thread suspend-resume SMP stress test

Adds a test to stress k_thread_suspend() and k_thread_resume() on
an SMP system. The test should take about 30 seconds.

Signed-off-by: Peter Mitsis <peter.mitsis@intel.com>

tests/kernel/smp_suspend/CMakeLists.txt

@@ -0,0 +1,12 @@
+# SPDX-License-Identifier: Apache-2.0
+
+cmake_minimum_required(VERSION 3.20.0)
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+project(smp)
+
+target_sources(app PRIVATE src/main.c)
+
+target_include_directories(app PRIVATE
+  ${ZEPHYR_BASE}/kernel/include
+  ${ZEPHYR_BASE}/arch/${ARCH}/include
+  )

tests/kernel/smp_suspend/prj.conf

@@ -0,0 +1,2 @@
+CONFIG_ZTEST=y
+CONFIG_SMP=y

tests/kernel/smp_suspend/src/main.c

@@ -0,0 +1,85 @@
+/*
+ * Copyright (c) 2024 Intel Corporation.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr/tc_util.h>
+#include <zephyr/ztest.h>
+#include <zephyr/kernel.h>
+
+#if CONFIG_MP_MAX_NUM_CPUS < 2
+#error "SMP test requires at least two CPUs!"
+#endif
+
+#define STACK_SIZE 1024
+
+#define NUM_THREADS 6
+
+K_THREAD_STACK_ARRAY_DEFINE(thread_stack, NUM_THREADS, STACK_SIZE);
+struct k_thread thread[NUM_THREADS];
+
+volatile uint64_t thread_counter[NUM_THREADS];
+
+static void thread_entry(void *p1, void *p2, void *p3)
+{
+	struct k_thread *resume_thread = p1;
+	unsigned int self_index = (unsigned int)(uintptr_t)p2;
+
+	while (1) {
+		if (resume_thread != NULL) {
+			k_thread_resume(resume_thread);
+		}
+
+		thread_counter[self_index]++;
+
+		if (self_index != 0) {
+			k_thread_suspend(k_current_get());
+		}
+	}
+}
+
+ZTEST(smp_suspend_resume, test_smp_thread_suspend_resume_stress)
+{
+	unsigned int  i;
+	uint64_t counter[NUM_THREADS] = {};
+
+	/* Create the threads */
+
+	printk("Starting ...\n");
+
+	for (i = 0; i < NUM_THREADS; i++) {
+
+		k_thread_create(&thread[i], thread_stack[i],
+				STACK_SIZE, thread_entry,
+				i < (NUM_THREADS - 1) ? &thread[i + 1] : NULL,
+				(void *)(uintptr_t)i, NULL,
+				10 - i, 0, K_FOREVER);
+
+		k_thread_suspend(&thread[i]);
+
+		k_thread_start(&thread[i]);
+	}
+
+	/*
+	 * All newly created test threads are currently in the suspend state.
+	 * Start the first thread.
+	 */
+
+	k_thread_resume(&thread[0]);
+
+	for (unsigned int iteration = 0; iteration < 30; iteration++) {
+		k_sleep(K_MSEC(1000));
+
+		for (i = 0; i < NUM_THREADS; i++) {
+			zassert_false(counter[i] == thread_counter[i],
+				      " -- Thread %u appears to be hung: %llu\n",
+				      i, thread_counter[i]);
+
+			counter[i] = thread_counter[i];
+
+		}
+	}
+}
+
+ZTEST_SUITE(smp_suspend_resume, NULL, NULL, NULL, NULL, NULL);

tests/kernel/smp_suspend/testcase.yaml

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+tests:
+  kernel.smp_suspend:
+    tags:
+      - kernel
+      - smp
+    filter: (CONFIG_MP_MAX_NUM_CPUS > 1)