benchmark silo added

[c11concurrency-benchmarks.git] / silo / spinlock.h

diff --git a/silo/spinlock.h b/silo/spinlock.h
new file mode 100644 (file)
index 0000000..8c3fd87
--- /dev/null
+++ b/silo/spinlock.h
@@ -0,0 +1,55 @@
+#ifndef _SPINLOCK_H_
+#define _SPINLOCK_H_
+
+#include <stdint.h>
+
+#include "amd64.h"
+#include "macros.h"
+#include "util.h"
+
+class spinlock {
+public:
+  spinlock() : value(0) {}
+
+  spinlock(const spinlock &) = delete;
+  spinlock(spinlock &&) = delete;
+  spinlock &operator=(const spinlock &) = delete;
+
+  inline void
+  lock()
+  {
+    // XXX: implement SPINLOCK_BACKOFF
+    uint32_t v = value;
+    while (v || !__sync_bool_compare_and_swap(&value, 0, 1)) {
+      nop_pause();
+      v = value;
+    }
+    COMPILER_MEMORY_FENCE;
+  }
+
+  inline bool
+  try_lock()
+  {
+    return __sync_bool_compare_and_swap(&value, 0, 1);
+  }
+
+  inline void
+  unlock()
+  {
+    INVARIANT(value);
+    value = 0;
+    COMPILER_MEMORY_FENCE;
+  }
+
+  // just for debugging
+  inline bool
+  is_locked() const
+  {
+    return value;
+  }
+
+private:
+  volatile uint32_t value;
+};
+
+#endif /* _SPINLOCK_H_ */