Mercurial > hg > truffle
annotate src/share/vm/gc_implementation/shared/gcUtil.hpp @ 986:62001a362ce9
6827605: new String intrinsics may prevent EA scalar replacement
6875866: Intrinsic for String.indexOf() is broken on x86 with SSE4.2
Summary: Modify String intrinsic methods to pass char[] pointers instead of string oops.
Reviewed-by: never
author | kvn |
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date | Mon, 14 Sep 2009 12:14:20 -0700 |
parents | 9ee9cf798b59 |
children | e018e6884bd8 |
rev | line source |
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0 | 1 /* |
337 | 2 * Copyright 2002-2008 Sun Microsystems, Inc. All Rights Reserved. |
0 | 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
4 * | |
5 * This code is free software; you can redistribute it and/or modify it | |
6 * under the terms of the GNU General Public License version 2 only, as | |
7 * published by the Free Software Foundation. | |
8 * | |
9 * This code is distributed in the hope that it will be useful, but WITHOUT | |
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
12 * version 2 for more details (a copy is included in the LICENSE file that | |
13 * accompanied this code). | |
14 * | |
15 * You should have received a copy of the GNU General Public License version | |
16 * 2 along with this work; if not, write to the Free Software Foundation, | |
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
18 * | |
19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, | |
20 * CA 95054 USA or visit www.sun.com if you need additional information or | |
21 * have any questions. | |
22 * | |
23 */ | |
24 | |
25 // Catch-all file for utility classes | |
26 | |
27 // A weighted average maintains a running, weighted average | |
28 // of some float value (templates would be handy here if we | |
29 // need different types). | |
30 // | |
31 // The average is adaptive in that we smooth it for the | |
32 // initial samples; we don't use the weight until we have | |
33 // enough samples for it to be meaningful. | |
34 // | |
35 // This serves as our best estimate of a future unknown. | |
36 // | |
37 class AdaptiveWeightedAverage : public CHeapObj { | |
38 private: | |
39 float _average; // The last computed average | |
40 unsigned _sample_count; // How often we've sampled this average | |
41 unsigned _weight; // The weight used to smooth the averages | |
42 // A higher weight favors the most | |
43 // recent data. | |
44 | |
45 protected: | |
46 float _last_sample; // The last value sampled. | |
47 | |
48 void increment_count() { _sample_count++; } | |
49 void set_average(float avg) { _average = avg; } | |
50 | |
51 // Helper function, computes an adaptive weighted average | |
52 // given a sample and the last average | |
53 float compute_adaptive_average(float new_sample, float average); | |
54 | |
55 public: | |
56 // Input weight must be between 0 and 100 | |
57 AdaptiveWeightedAverage(unsigned weight) : | |
58 _average(0.0), _sample_count(0), _weight(weight), _last_sample(0.0) { | |
59 } | |
60 | |
268
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61 void clear() { |
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62 _average = 0; |
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63 _sample_count = 0; |
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64 _last_sample = 0; |
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65 } |
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66 |
0 | 67 // Accessors |
68 float average() const { return _average; } | |
69 unsigned weight() const { return _weight; } | |
70 unsigned count() const { return _sample_count; } | |
71 float last_sample() const { return _last_sample; } | |
72 | |
73 // Update data with a new sample. | |
74 void sample(float new_sample); | |
75 | |
76 static inline float exp_avg(float avg, float sample, | |
77 unsigned int weight) { | |
78 assert(0 <= weight && weight <= 100, "weight must be a percent"); | |
79 return (100.0F - weight) * avg / 100.0F + weight * sample / 100.0F; | |
80 } | |
81 static inline size_t exp_avg(size_t avg, size_t sample, | |
82 unsigned int weight) { | |
83 // Convert to float and back to avoid integer overflow. | |
84 return (size_t)exp_avg((float)avg, (float)sample, weight); | |
85 } | |
86 }; | |
87 | |
88 | |
89 // A weighted average that includes a deviation from the average, | |
90 // some multiple of which is added to the average. | |
91 // | |
92 // This serves as our best estimate of an upper bound on a future | |
93 // unknown. | |
94 class AdaptivePaddedAverage : public AdaptiveWeightedAverage { | |
95 private: | |
96 float _padded_avg; // The last computed padded average | |
97 float _deviation; // Running deviation from the average | |
98 unsigned _padding; // A multiple which, added to the average, | |
99 // gives us an upper bound guess. | |
100 | |
101 protected: | |
102 void set_padded_average(float avg) { _padded_avg = avg; } | |
103 void set_deviation(float dev) { _deviation = dev; } | |
104 | |
105 public: | |
106 AdaptivePaddedAverage() : | |
107 AdaptiveWeightedAverage(0), | |
108 _padded_avg(0.0), _deviation(0.0), _padding(0) {} | |
109 | |
110 AdaptivePaddedAverage(unsigned weight, unsigned padding) : | |
111 AdaptiveWeightedAverage(weight), | |
112 _padded_avg(0.0), _deviation(0.0), _padding(padding) {} | |
113 | |
114 // Placement support | |
115 void* operator new(size_t ignored, void* p) { return p; } | |
116 // Allocator | |
117 void* operator new(size_t size) { return CHeapObj::operator new(size); } | |
118 | |
119 // Accessor | |
120 float padded_average() const { return _padded_avg; } | |
121 float deviation() const { return _deviation; } | |
122 unsigned padding() const { return _padding; } | |
123 | |
268
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124 void clear() { |
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125 AdaptiveWeightedAverage::clear(); |
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126 _padded_avg = 0; |
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127 _deviation = 0; |
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128 } |
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129 |
0 | 130 // Override |
131 void sample(float new_sample); | |
132 }; | |
133 | |
134 // A weighted average that includes a deviation from the average, | |
135 // some multiple of which is added to the average. | |
136 // | |
137 // This serves as our best estimate of an upper bound on a future | |
138 // unknown. | |
139 // A special sort of padded average: it doesn't update deviations | |
140 // if the sample is zero. The average is allowed to change. We're | |
141 // preventing the zero samples from drastically changing our padded | |
142 // average. | |
143 class AdaptivePaddedNoZeroDevAverage : public AdaptivePaddedAverage { | |
144 public: | |
145 AdaptivePaddedNoZeroDevAverage(unsigned weight, unsigned padding) : | |
146 AdaptivePaddedAverage(weight, padding) {} | |
147 // Override | |
148 void sample(float new_sample); | |
149 }; | |
150 // Use a least squares fit to a set of data to generate a linear | |
151 // equation. | |
152 // y = intercept + slope * x | |
153 | |
154 class LinearLeastSquareFit : public CHeapObj { | |
155 double _sum_x; // sum of all independent data points x | |
156 double _sum_x_squared; // sum of all independent data points x**2 | |
157 double _sum_y; // sum of all dependent data points y | |
158 double _sum_xy; // sum of all x * y. | |
159 double _intercept; // constant term | |
160 double _slope; // slope | |
161 // The weighted averages are not currently used but perhaps should | |
162 // be used to get decaying averages. | |
163 AdaptiveWeightedAverage _mean_x; // weighted mean of independent variable | |
164 AdaptiveWeightedAverage _mean_y; // weighted mean of dependent variable | |
165 | |
166 public: | |
167 LinearLeastSquareFit(unsigned weight); | |
168 void update(double x, double y); | |
169 double y(double x); | |
170 double slope() { return _slope; } | |
171 // Methods to decide if a change in the dependent variable will | |
172 // achive a desired goal. Note that these methods are not | |
173 // complementary and both are needed. | |
174 bool decrement_will_decrease(); | |
175 bool increment_will_decrease(); | |
176 }; | |
177 | |
178 class GCPauseTimer : StackObj { | |
179 elapsedTimer* _timer; | |
180 public: | |
181 GCPauseTimer(elapsedTimer* timer) { | |
182 _timer = timer; | |
183 _timer->stop(); | |
184 } | |
185 ~GCPauseTimer() { | |
186 _timer->start(); | |
187 } | |
188 }; |