1/*
2 * Copyright (c) 2018, Red Hat, Inc. All rights reserved.
3 *
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation.
7 *
8 * This code is distributed in the hope that it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
11 * version 2 for more details (a copy is included in the LICENSE file that
12 * accompanied this code).
13 *
14 * You should have received a copy of the GNU General Public License version
15 * 2 along with this work; if not, write to the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
17 *
18 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
19 * or visit www.oracle.com if you need additional information or have any
20 * questions.
21 *
22 */
23
24#ifndef SHARE_GC_SHENANDOAH_SHENANDOAHNUMBERSEQ_HPP
25#define SHARE_GC_SHENANDOAH_SHENANDOAHNUMBERSEQ_HPP
26
27#include "utilities/numberSeq.hpp"
28
29// HDR sequence stores the low-resolution high-dynamic-range values.
30// It does so by maintaining the double array, where first array defines
31// the magnitude of the value being stored, and the second array maintains
32// the low resolution histogram within that magnitude. For example, storing
33// 4.352819 * 10^3 increments the bucket _hdr[3][435]. This allows for
34// memory efficient storage of huge amount of samples.
35//
36// Accepts positive numbers only.
37class HdrSeq: public NumberSeq {
38private:
39 enum PrivateConstants {
40 ValBuckets = 512,
41 MagBuckets = 24,
42 MagMinimum = -12
43 };
44 int** _hdr;
45
46public:
47 HdrSeq();
48 ~HdrSeq();
49
50 virtual void add(double val);
51 double percentile(double level) const;
52};
53
54// Binary magnitude sequence stores the power-of-two histogram.
55// It has very low memory requirements, and is thread-safe. When accuracy
56// is not needed, it is preferred over HdrSeq.
57class BinaryMagnitudeSeq {
58private:
59 size_t _sum;
60 size_t* _mags;
61
62public:
63 BinaryMagnitudeSeq();
64 ~BinaryMagnitudeSeq();
65
66 void add(size_t val);
67 size_t num() const;
68 size_t level(int level) const;
69 size_t sum() const;
70 int min_level() const;
71 int max_level() const;
72};
73
74#endif // SHARE_GC_SHENANDOAH_SHENANDOAHNUMBERSEQ_HPP
75