--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/gc/cms/allocationStats.hpp Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,169 @@
+/*
+ * Copyright (c) 2001, 2015, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#ifndef SHARE_VM_GC_CMS_ALLOCATIONSTATS_HPP
+#define SHARE_VM_GC_CMS_ALLOCATIONSTATS_HPP
+
+#include "gc/shared/gcUtil.hpp"
+#include "logging/log.hpp"
+#include "memory/allocation.hpp"
+#include "utilities/globalDefinitions.hpp"
+#include "utilities/macros.hpp"
+
+class AllocationStats VALUE_OBJ_CLASS_SPEC {
+ // A duration threshold (in ms) used to filter
+ // possibly unreliable samples.
+ static float _threshold;
+
+ // We measure the demand between the end of the previous sweep and
+ // beginning of this sweep:
+ // Count(end_last_sweep) - Count(start_this_sweep)
+ // + split_births(between) - split_deaths(between)
+ // The above number divided by the time since the end of the
+ // previous sweep gives us a time rate of demand for blocks
+ // of this size. We compute a padded average of this rate as
+ // our current estimate for the time rate of demand for blocks
+ // of this size. Similarly, we keep a padded average for the time
+ // between sweeps. Our current estimate for demand for blocks of
+ // this size is then simply computed as the product of these two
+ // estimates.
+ AdaptivePaddedAverage _demand_rate_estimate;
+
+ ssize_t _desired; // Demand estimate computed as described above
+ ssize_t _coal_desired; // desired +/- small-percent for tuning coalescing
+
+ ssize_t _surplus; // count - (desired +/- small-percent),
+ // used to tune splitting in best fit
+ ssize_t _bfr_surp; // surplus at start of current sweep
+ ssize_t _prev_sweep; // count from end of previous sweep
+ ssize_t _before_sweep; // count from before current sweep
+ ssize_t _coal_births; // additional chunks from coalescing
+ ssize_t _coal_deaths; // loss from coalescing
+ ssize_t _split_births; // additional chunks from splitting
+ ssize_t _split_deaths; // loss from splitting
+ size_t _returned_bytes; // number of bytes returned to list.
+ public:
+ void initialize(bool split_birth = false) {
+ AdaptivePaddedAverage* dummy =
+ new (&_demand_rate_estimate) AdaptivePaddedAverage(CMS_FLSWeight,
+ CMS_FLSPadding);
+ _desired = 0;
+ _coal_desired = 0;
+ _surplus = 0;
+ _bfr_surp = 0;
+ _prev_sweep = 0;
+ _before_sweep = 0;
+ _coal_births = 0;
+ _coal_deaths = 0;
+ _split_births = (split_birth ? 1 : 0);
+ _split_deaths = 0;
+ _returned_bytes = 0;
+ }
+
+ AllocationStats() {
+ initialize();
+ }
+
+ // The rate estimate is in blocks per second.
+ void compute_desired(size_t count,
+ float inter_sweep_current,
+ float inter_sweep_estimate,
+ float intra_sweep_estimate) {
+ // If the latest inter-sweep time is below our granularity
+ // of measurement, we may call in here with
+ // inter_sweep_current == 0. However, even for suitably small
+ // but non-zero inter-sweep durations, we may not trust the accuracy
+ // of accumulated data, since it has not been "integrated"
+ // (read "low-pass-filtered") long enough, and would be
+ // vulnerable to noisy glitches. In such cases, we
+ // ignore the current sample and use currently available
+ // historical estimates.
+ assert(prev_sweep() + split_births() + coal_births() // "Total Production Stock"
+ >= split_deaths() + coal_deaths() + (ssize_t)count, // "Current stock + depletion"
+ "Conservation Principle");
+ if (inter_sweep_current > _threshold) {
+ ssize_t demand = prev_sweep() - (ssize_t)count + split_births() + coal_births()
+ - split_deaths() - coal_deaths();
+ assert(demand >= 0,
+ "Demand (" SSIZE_FORMAT ") should be non-negative for "
+ PTR_FORMAT " (size=" SIZE_FORMAT ")",
+ demand, p2i(this), count);
+ // Defensive: adjust for imprecision in event counting
+ if (demand < 0) {
+ demand = 0;
+ }
+ float old_rate = _demand_rate_estimate.padded_average();
+ float rate = ((float)demand)/inter_sweep_current;
+ _demand_rate_estimate.sample(rate);
+ float new_rate = _demand_rate_estimate.padded_average();
+ ssize_t old_desired = _desired;
+ float delta_ise = (CMSExtrapolateSweep ? intra_sweep_estimate : 0.0);
+ _desired = (ssize_t)(new_rate * (inter_sweep_estimate + delta_ise));
+ log_trace(gc, freelist)("demand: " SSIZE_FORMAT ", old_rate: %f, current_rate: %f, "
+ "new_rate: %f, old_desired: " SSIZE_FORMAT ", new_desired: " SSIZE_FORMAT,
+ demand, old_rate, rate, new_rate, old_desired, _desired);
+ }
+ }
+
+ ssize_t desired() const { return _desired; }
+ void set_desired(ssize_t v) { _desired = v; }
+
+ ssize_t coal_desired() const { return _coal_desired; }
+ void set_coal_desired(ssize_t v) { _coal_desired = v; }
+
+ ssize_t surplus() const { return _surplus; }
+ void set_surplus(ssize_t v) { _surplus = v; }
+ void increment_surplus() { _surplus++; }
+ void decrement_surplus() { _surplus--; }
+
+ ssize_t bfr_surp() const { return _bfr_surp; }
+ void set_bfr_surp(ssize_t v) { _bfr_surp = v; }
+ ssize_t prev_sweep() const { return _prev_sweep; }
+ void set_prev_sweep(ssize_t v) { _prev_sweep = v; }
+ ssize_t before_sweep() const { return _before_sweep; }
+ void set_before_sweep(ssize_t v) { _before_sweep = v; }
+
+ ssize_t coal_births() const { return _coal_births; }
+ void set_coal_births(ssize_t v) { _coal_births = v; }
+ void increment_coal_births() { _coal_births++; }
+
+ ssize_t coal_deaths() const { return _coal_deaths; }
+ void set_coal_deaths(ssize_t v) { _coal_deaths = v; }
+ void increment_coal_deaths() { _coal_deaths++; }
+
+ ssize_t split_births() const { return _split_births; }
+ void set_split_births(ssize_t v) { _split_births = v; }
+ void increment_split_births() { _split_births++; }
+
+ ssize_t split_deaths() const { return _split_deaths; }
+ void set_split_deaths(ssize_t v) { _split_deaths = v; }
+ void increment_split_deaths() { _split_deaths++; }
+
+ NOT_PRODUCT(
+ size_t returned_bytes() const { return _returned_bytes; }
+ void set_returned_bytes(size_t v) { _returned_bytes = v; }
+ )
+};
+
+#endif // SHARE_VM_GC_CMS_ALLOCATIONSTATS_HPP