1 files changed, 79 insertions, 0 deletions
diff --git a/src/common/DecayCounter.cc b/src/common/DecayCounter.cc
new file mode 100644
index 000000000..4e9e68cc1
--- /dev/null
+++ b/src/common/DecayCounter.cc
@@ -0,0 +1,79 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+/*
+ * Ceph - scalable distributed file system
+ *
+ * Copyright (C) 2004-2006 Sage Weil <sage@newdream.net>
+ *
+ * This is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License version 2.1, as published by the Free Software
+ * Foundation.  See file COPYING.
+ *
+ */
+
+#include "DecayCounter.h"
+#include "Formatter.h"
+
+#include "include/encoding.h"
+
+void DecayCounter::encode(ceph::buffer::list& bl) const
+{
+  decay();
+  ENCODE_START(5, 4, bl);
+  encode(val, bl);
+  ENCODE_FINISH(bl);
+}
+
+void DecayCounter::decode(ceph::buffer::list::const_iterator &p)
+{
+  DECODE_START_LEGACY_COMPAT_LEN(5, 4, 4, p);
+  if (struct_v < 2) {
+    double k = 0.0;
+    decode(k, p);
+  }
+  if (struct_v < 3) {
+    double k = 0.0;
+    decode(k, p);
+  }
+  decode(val, p);
+  if (struct_v < 5) {
+    double delta, _;
+    decode(delta, p);
+    val += delta;
+    decode(_, p); /* velocity */
+  }
+  last_decay = clock::now();
+  DECODE_FINISH(p);
+}
+
+void DecayCounter::dump(ceph::Formatter *f) const
+{
+  decay();
+  f->dump_float("value", val);
+  f->dump_float("halflife", rate.get_halflife());
+}
+
+void DecayCounter::generate_test_instances(std::list<DecayCounter*>& ls)
+{
+  DecayCounter *counter = new DecayCounter();
+  counter->val = 3.0;
+  ls.push_back(counter);
+  counter = new DecayCounter();
+  ls.push_back(counter);
+}
+
+void DecayCounter::decay(double delta) const
+{
+  auto now = clock::now();
+  double el = std::chrono::duration<double>(now - last_decay).count();
+
+  // calculate new value
+  double newval = val * exp(el * rate.k) + delta;
+  if (newval < .01) {
+    newval = 0.0;
+  }
+
+  val = newval;
+  last_decay = now;
+}