From 4bb3b3cec7041c0285ea82b668e8ec223d7bccf5 Mon Sep 17 00:00:00 2001
From: Dmitry Selyutin <ghostmansd@gmail.com>
Date: Mon, 5 Apr 2021 20:48:50 +0300
Subject: [PATCH] stdatomic: simple counter test

---
 tests/tests2/124_atomic_counter.c      | 75 ++++++++++++++++++++++++++
 tests/tests2/124_atomic_counter.expect |  2 +
 tests/tests2/Makefile                  |  6 +++
 3 files changed, 83 insertions(+)
 create mode 100644 tests/tests2/124_atomic_counter.c
 create mode 100644 tests/tests2/124_atomic_counter.expect

diff --git a/tests/tests2/124_atomic_counter.c b/tests/tests2/124_atomic_counter.c
new file mode 100644
index 00000000..a817fc26
--- /dev/null
+++ b/tests/tests2/124_atomic_counter.c
@@ -0,0 +1,75 @@
+#include <stddef.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <pthread.h>
+#include <stdatomic.h>
+
+#define NR_THREADS 16
+#define NR_STEPS   ((uint32_t)UINT16_MAX * 4)
+
+#define BUG_ON(COND) \
+    do { \
+        if (!!(COND)) \
+            abort(); \
+    } while (0)
+
+static
+void *adder_simple(void *arg)
+{
+    size_t step;
+    atomic_size_t *counter = arg;
+
+    for (step = 0; step < NR_STEPS; ++step)
+        atomic_fetch_add_explicit(counter, 1, memory_order_relaxed);
+
+    return NULL;
+}
+
+static
+void *adder_cmpxchg(void *arg)
+{
+    size_t step;
+    atomic_size_t *counter = arg;
+
+    for (step = 0; step < NR_STEPS; ++step) {
+        size_t xchg;
+        size_t cmp = atomic_load_explicit(counter, memory_order_relaxed);
+
+        do {
+            xchg = (cmp + 1);
+        } while (!atomic_compare_exchange_strong_explicit(counter,
+            &cmp, xchg, memory_order_relaxed, memory_order_relaxed));
+    }
+
+    return NULL;
+}
+
+static
+void atomic_counter_test(void *(*adder)(void *arg))
+{
+    size_t index;
+    atomic_size_t counter;
+    pthread_t thread[NR_THREADS];
+
+    atomic_init(&counter, 0);
+
+    for (index = 0; index < NR_THREADS; ++index)
+        BUG_ON(pthread_create(&thread[index], NULL, adder, (void *)&counter));
+
+    for (index = 0; index < NR_THREADS; ++index)
+        BUG_ON(pthread_join(thread[index], NULL));
+
+    if (atomic_load(&counter) == (NR_THREADS * NR_STEPS))
+        printf("SUCCESS\n");
+    else
+        printf("FAILURE\n");
+}
+
+int main(void)
+{
+    atomic_counter_test(adder_simple);
+    atomic_counter_test(adder_cmpxchg);
+
+    return 0;
+}
diff --git a/tests/tests2/124_atomic_counter.expect b/tests/tests2/124_atomic_counter.expect
new file mode 100644
index 00000000..1db2652c
--- /dev/null
+++ b/tests/tests2/124_atomic_counter.expect
@@ -0,0 +1,2 @@
+SUCCESS
+SUCCESS
diff --git a/tests/tests2/Makefile b/tests/tests2/Makefile
index 1eaaa756..f21b9762 100644
--- a/tests/tests2/Makefile
+++ b/tests/tests2/Makefile
@@ -116,6 +116,12 @@ ifneq ($(CONFIG_bcheck),no)
 122_vla_reuse.test: FLAGS += -b
 endif
 
+# this test needs pthread and is currently supported on x86 platforms
+ifneq (,$(filter i386 x86_64,$(ARCH)))
+ SKIP += 124_atomic_counter.test
+endif
+124_atomic_counter.test: FLAGS += -pthread
+
 # Filter source directory in warnings/errors (out-of-tree builds)
 FILTER = 2>&1 | sed -e 's,$(SRC)/,,g'