tests: posix: improvements to pthread_pressure test

* allow `qemu_cortex_a53`
* disallow `qemu_leon3
* remove `TEST_DURATION_S` range
* additional report formatting

Signed-off-by: Christopher Friedt <cfriedt@meta.com>

tests/posix/common/prj.conf

@@ -8,5 +8,3 @@ CONFIG_POSIX_MQUEUE=y
 CONFIG_HEAP_MEM_POOL_SIZE=4096
 CONFIG_MAX_THREAD_BYTES=4
 CONFIG_THREAD_NAME=y
-
-CONFIG_SMP=n

tests/posix/pthread_pressure/Kconfig

@@ -9,21 +9,13 @@ config TEST_NUM_CPUS
 	range 1 MP_NUM_CPUS
 	default MP_NUM_CPUS
 	help
-	  The number of parallel threads to run during the test. The test
-	  thread itself yields so that all cores have some probability of
-	  causing racey behaviour.
+	  The number of parallel threads to run during the test.
 
 config TEST_DURATION_S
 	int "Number of seconds to run the test"
-	range 1 21600
 	default 5
 	help
-	   Duration for the test, in seconds. The range has a reblatively high
-	   upper bound because we should expect that pthread_create() and
-	   pthread_join() are stable enough to run for an arbitrarily long
-	   period of time without encountering any race conditions.
-
-	   Some exceptions apply, notably Qemu SMP targets.
+	   Duration for the test, in seconds.
 
 config TEST_DELAY_US
 	int "Microseconds to delay between pthread join and create"
@@ -37,7 +29,7 @@ config TEST_STACK_SIZE
 	default 512 if !64_BIT
 	default 1024 if 64_BIT
 	help
-	  The minimal stack size required to run a no-op thread.
+	  The minimal stack size required to run a minimal thread.
 
 config TEST_KTHREADS
 	bool "Test k_threads"
@@ -55,5 +47,4 @@ config TEST_EXTRA_ASSERTIONS
 	bool "Add extra assertions into the hot path"
 	default y
 	help
-	  On Qemu SMP targets, this can potentially lead to "scheduler noise"
-	  leaking in from the host system, which can cause the test to fail.
+	  This can be disabled for benchmarking.

tests/posix/pthread_pressure/prj.conf

@@ -1,3 +1,11 @@
 CONFIG_ZTEST=y
 CONFIG_ZTEST_NEW_API=y
 CONFIG_POSIX_API=y
+
+## Note: for benchmarking purposes, uncomment the Kconfig below
+# CONFIG_TEST_DURATION_S=60
+# CONFIG_TEST_EXTRA_ASSERTIONS=n
+# CONFIG_ASSERT=n
+
+## Optionally, uncomment this to only test pthreads:
+# CONFIG_TEST_KTHREADS=n

tests/posix/pthread_pressure/src/main.c

@@ -36,13 +36,16 @@ static bool alive[NUM_THREADS];
 static K_THREAD_STACK_ARRAY_DEFINE(thread_stacks, NUM_THREADS, STACK_SIZE);
 
 static struct k_thread k_threads[NUM_THREADS];
-static size_t counters[NUM_THREADS];
+static uint64_t counters[NUM_THREADS];
+static uint64_t prev_counters[NUM_THREADS];
 
 static void print_stats(uint64_t now, uint64_t end)
 {
 	printk("now (ms): %llu end (ms): %llu\n", now, end);
 	for (int i = 0; i < NUM_THREADS; ++i) {
-		printk("Thread %d created and joined %zu times\n", i, counters[i]);
+		printk("Thread %d created and joined %llu times (%llu joins/s)\n", i, counters[i],
+		       (counters[i] - prev_counters[i]) / UPDATE_INTERVAL_S);
+		prev_counters[i] = counters[i];
 	}
 }
 
@@ -55,6 +58,7 @@ static void test_create_join_common(const char *tag, create_fn create, join_fn j
 	uint64_t update_ms = now_ms + MSEC_PER_SEC * UPDATE_INTERVAL_S;
 
 	printk("BOARD: %s\n", CONFIG_BOARD);
+	printk("CONFIG_SMP: %s\n", IS_ENABLED(CONFIG_SMP) ? "y" : "n");
 	printk("NUM_THREADS: %u\n", NUM_THREADS);
 	printk("TEST_NUM_CPUS: %u\n", CONFIG_TEST_NUM_CPUS);
 	printk("TEST_DURATION_S: %u\n", CONFIG_TEST_DURATION_S);
@@ -62,6 +66,7 @@ static void test_create_join_common(const char *tag, create_fn create, join_fn j
 
 	for (i = 0; i < NUM_THREADS; ++i) {
 		/* spawn thread i */
+		prev_counters[i] = 0;
 		ret = create(i);
 		if (IS_ENABLED(CONFIG_TEST_EXTRA_ASSERTIONS)) {
 			zassert_ok(ret, "%s_create(%d)[%zu] failed: %d", tag, i, counters[i], ret);

tests/posix/pthread_pressure/testcase.yaml

@@ -6,7 +6,6 @@ common:
   integration_platforms:
     - qemu_riscv64_smp
   platform_exclude:
-    - qemu_cortex_a53
-    - qemu_cortex_a53_smp
+    - qemu_leon3
 tests:
   portability.posix.pthread_pressure: {}