--- /dev/null
+// -*- 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"
+
+void DecayCounter::encode(bufferlist& bl) const
+{
+ ENCODE_START(4, 4, bl);
+ ::encode(val, bl);
+ ::encode(delta, bl);
+ ::encode(vel, bl);
+ ENCODE_FINISH(bl);
+}
+
+void DecayCounter::decode(const utime_t &t, bufferlist::iterator &p)
+{
+ DECODE_START_LEGACY_COMPAT_LEN(4, 4, 4, p);
+ if (struct_v < 2) {
+ double half_life;
+ ::decode(half_life, p);
+ }
+ if (struct_v < 3) {
+ double k;
+ ::decode(k, p);
+ }
+ ::decode(val, p);
+ ::decode(delta, p);
+ ::decode(vel, p);
+ DECODE_FINISH(p);
+}
+
+void DecayCounter::dump(Formatter *f) const
+{
+ f->dump_float("value", val);
+ f->dump_float("delta", delta);
+ f->dump_float("velocity", vel);
+}
+
+void DecayCounter::generate_test_instances(list<DecayCounter*>& ls)
+{
+ utime_t fake_time;
+ DecayCounter *counter = new DecayCounter(fake_time);
+ counter->val = 3.0;
+ counter->delta = 2.0;
+ counter->vel = 1.0;
+ ls.push_back(counter);
+ counter = new DecayCounter(fake_time);
+ ls.push_back(counter);
+}
+
+void DecayCounter::decay(utime_t now, const DecayRate &rate)
+{
+ utime_t el = now;
+ el -= last_decay;
+
+ if (el.sec() >= 1) {
+ // calculate new value
+ double newval = (val+delta) * exp((double)el * rate.k);
+ if (newval < .01)
+ newval = 0.0;
+
+ // calculate velocity approx
+ vel += (newval - val) * (double)el;
+ vel *= exp((double)el * rate.k);
+
+ val = newval;
+ delta = 0;
+ last_decay = now;
+ }
+}