benchmark silo added

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

diff --git a/silo/spinbarrier.h b/silo/spinbarrier.h
new file mode 100644 (file)
index 0000000..966f880
--- /dev/null
+++ b/silo/spinbarrier.h
@@ -0,0 +1,53 @@
+#ifndef _SPINBARRIER_H_
+#define _SPINBARRIER_H_
+
+#include "amd64.h"
+#include "macros.h"
+#include "util.h"
+
+/**
+ * Barrier implemented by spinning
+ */
+
+class spin_barrier {
+public:
+  spin_barrier(size_t n)
+    : n(n)
+  {
+    ALWAYS_ASSERT(n > 0);
+  }
+
+  spin_barrier(const spin_barrier &) = delete;
+  spin_barrier(spin_barrier &&) = delete;
+  spin_barrier &operator=(const spin_barrier &) = delete;
+
+  ~spin_barrier()
+  {
+    ALWAYS_ASSERT(n == 0);
+  }
+
+  void
+  count_down()
+  {
+    // written like this (instead of using __sync_fetch_and_add())
+    // so we can have assertions
+    for (;;) {
+      size_t copy = n;
+      ALWAYS_ASSERT(copy > 0);
+      if (__sync_bool_compare_and_swap(&n, copy, copy - 1))
+        return;
+    }
+  }
+
+  void
+  wait_for()
+  {
+    while (n > 0)
+      nop_pause();
+  }
+
+private:
+  volatile size_t n;
+};
+
+#endif /* _SPINBARRIER_H_ */