1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/src/share/vm/memory/allocationStats.hpp Sat Dec 01 00:00:00 2007 +0000
1.3 @@ -0,0 +1,136 @@
1.4 +/*
1.5 + * Copyright 2001-2005 Sun Microsystems, Inc. All Rights Reserved.
1.6 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.7 + *
1.8 + * This code is free software; you can redistribute it and/or modify it
1.9 + * under the terms of the GNU General Public License version 2 only, as
1.10 + * published by the Free Software Foundation.
1.11 + *
1.12 + * This code is distributed in the hope that it will be useful, but WITHOUT
1.13 + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
1.14 + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
1.15 + * version 2 for more details (a copy is included in the LICENSE file that
1.16 + * accompanied this code).
1.17 + *
1.18 + * You should have received a copy of the GNU General Public License version
1.19 + * 2 along with this work; if not, write to the Free Software Foundation,
1.20 + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
1.21 + *
1.22 + * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
1.23 + * CA 95054 USA or visit www.sun.com if you need additional information or
1.24 + * have any questions.
1.25 + *
1.26 + */
1.27 +
1.28 +class AllocationStats VALUE_OBJ_CLASS_SPEC {
1.29 + // A duration threshold (in ms) used to filter
1.30 + // possibly unreliable samples.
1.31 + static float _threshold;
1.32 +
1.33 + // We measure the demand between the end of the previous sweep and
1.34 + // beginning of this sweep:
1.35 + // Count(end_last_sweep) - Count(start_this_sweep)
1.36 + // + splitBirths(between) - splitDeaths(between)
1.37 + // The above number divided by the time since the start [END???] of the
1.38 + // previous sweep gives us a time rate of demand for blocks
1.39 + // of this size. We compute a padded average of this rate as
1.40 + // our current estimate for the time rate of demand for blocks
1.41 + // of this size. Similarly, we keep a padded average for the time
1.42 + // between sweeps. Our current estimate for demand for blocks of
1.43 + // this size is then simply computed as the product of these two
1.44 + // estimates.
1.45 + AdaptivePaddedAverage _demand_rate_estimate;
1.46 +
1.47 + ssize_t _desired; // Estimate computed as described above
1.48 + ssize_t _coalDesired; // desired +/- small-percent for tuning coalescing
1.49 +
1.50 + ssize_t _surplus; // count - (desired +/- small-percent),
1.51 + // used to tune splitting in best fit
1.52 + ssize_t _bfrSurp; // surplus at start of current sweep
1.53 + ssize_t _prevSweep; // count from end of previous sweep
1.54 + ssize_t _beforeSweep; // count from before current sweep
1.55 + ssize_t _coalBirths; // additional chunks from coalescing
1.56 + ssize_t _coalDeaths; // loss from coalescing
1.57 + ssize_t _splitBirths; // additional chunks from splitting
1.58 + ssize_t _splitDeaths; // loss from splitting
1.59 + size_t _returnedBytes; // number of bytes returned to list.
1.60 + public:
1.61 + void initialize() {
1.62 + AdaptivePaddedAverage* dummy =
1.63 + new (&_demand_rate_estimate) AdaptivePaddedAverage(CMS_FLSWeight,
1.64 + CMS_FLSPadding);
1.65 + _desired = 0;
1.66 + _coalDesired = 0;
1.67 + _surplus = 0;
1.68 + _bfrSurp = 0;
1.69 + _prevSweep = 0;
1.70 + _beforeSweep = 0;
1.71 + _coalBirths = 0;
1.72 + _coalDeaths = 0;
1.73 + _splitBirths = 0;
1.74 + _splitDeaths = 0;
1.75 + _returnedBytes = 0;
1.76 + }
1.77 +
1.78 + AllocationStats() {
1.79 + initialize();
1.80 + }
1.81 + // The rate estimate is in blocks per second.
1.82 + void compute_desired(size_t count,
1.83 + float inter_sweep_current,
1.84 + float inter_sweep_estimate) {
1.85 + // If the latest inter-sweep time is below our granularity
1.86 + // of measurement, we may call in here with
1.87 + // inter_sweep_current == 0. However, even for suitably small
1.88 + // but non-zero inter-sweep durations, we may not trust the accuracy
1.89 + // of accumulated data, since it has not been "integrated"
1.90 + // (read "low-pass-filtered") long enough, and would be
1.91 + // vulnerable to noisy glitches. In such cases, we
1.92 + // ignore the current sample and use currently available
1.93 + // historical estimates.
1.94 + if (inter_sweep_current > _threshold) {
1.95 + ssize_t demand = prevSweep() - count + splitBirths() - splitDeaths();
1.96 + float rate = ((float)demand)/inter_sweep_current;
1.97 + _demand_rate_estimate.sample(rate);
1.98 + _desired = (ssize_t)(_demand_rate_estimate.padded_average()
1.99 + *inter_sweep_estimate);
1.100 + }
1.101 + }
1.102 +
1.103 + ssize_t desired() const { return _desired; }
1.104 + ssize_t coalDesired() const { return _coalDesired; }
1.105 + void set_coalDesired(ssize_t v) { _coalDesired = v; }
1.106 +
1.107 + ssize_t surplus() const { return _surplus; }
1.108 + void set_surplus(ssize_t v) { _surplus = v; }
1.109 + void increment_surplus() { _surplus++; }
1.110 + void decrement_surplus() { _surplus--; }
1.111 +
1.112 + ssize_t bfrSurp() const { return _bfrSurp; }
1.113 + void set_bfrSurp(ssize_t v) { _bfrSurp = v; }
1.114 + ssize_t prevSweep() const { return _prevSweep; }
1.115 + void set_prevSweep(ssize_t v) { _prevSweep = v; }
1.116 + ssize_t beforeSweep() const { return _beforeSweep; }
1.117 + void set_beforeSweep(ssize_t v) { _beforeSweep = v; }
1.118 +
1.119 + ssize_t coalBirths() const { return _coalBirths; }
1.120 + void set_coalBirths(ssize_t v) { _coalBirths = v; }
1.121 + void increment_coalBirths() { _coalBirths++; }
1.122 +
1.123 + ssize_t coalDeaths() const { return _coalDeaths; }
1.124 + void set_coalDeaths(ssize_t v) { _coalDeaths = v; }
1.125 + void increment_coalDeaths() { _coalDeaths++; }
1.126 +
1.127 + ssize_t splitBirths() const { return _splitBirths; }
1.128 + void set_splitBirths(ssize_t v) { _splitBirths = v; }
1.129 + void increment_splitBirths() { _splitBirths++; }
1.130 +
1.131 + ssize_t splitDeaths() const { return _splitDeaths; }
1.132 + void set_splitDeaths(ssize_t v) { _splitDeaths = v; }
1.133 + void increment_splitDeaths() { _splitDeaths++; }
1.134 +
1.135 + NOT_PRODUCT(
1.136 + size_t returnedBytes() const { return _returnedBytes; }
1.137 + void set_returnedBytes(size_t v) { _returnedBytes = v; }
1.138 + )
1.139 +};
