1/*
2 * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25#include "precompiled.hpp"
26#include "gc/g1/g1Predictions.hpp"
27#include "unittest.hpp"
28
29static const double epsilon = 1e-6;
30
31// Some basic formula tests with confidence = 0.0
32TEST_VM(G1Predictions, basic_predictions) {
33 G1Predictions predictor(0.0);
34 TruncatedSeq s;
35
36 double p0 = predictor.get_new_prediction(&s);
37 ASSERT_LT(p0, epsilon) << "Initial prediction of empty sequence must be 0.0";
38
39 s.add(5.0);
40 double p1 = predictor.get_new_prediction(&s);
41 ASSERT_NEAR(p1, 5.0, epsilon);
42
43 for (int i = 0; i < 40; i++) {
44 s.add(5.0);
45 }
46 double p2 = predictor.get_new_prediction(&s);
47 ASSERT_NEAR(p2, 5.0, epsilon);
48}
49
50// The following tests checks that the initial predictions are based on
51// the average of the sequence and not on the stddev (which is 0).
52TEST_VM(G1Predictions, average_not_stdev_predictions) {
53 G1Predictions predictor(0.5);
54 TruncatedSeq s;
55
56 s.add(1.0);
57 double p1 = predictor.get_new_prediction(&s);
58 ASSERT_GT(p1, s.davg()) << "First prediction must be greater than average";
59
60 s.add(1.0);
61 double p2 = predictor.get_new_prediction(&s);
62 ASSERT_GT(p1, p2) << "First prediction must be greater than second";
63
64 s.add(1.0);
65 double p3 = predictor.get_new_prediction(&s);
66 ASSERT_GT(p2, p3) << "Second prediction must be greater than third";
67
68 s.add(1.0);
69 s.add(1.0); // Five elements are now in the sequence.
70 double p4 = predictor.get_new_prediction(&s);
71 ASSERT_LT(p4, p3) << "Fourth prediction must be smaller than third";
72 ASSERT_NEAR(p4, 1.0, epsilon);
73}
74
75// The following tests checks that initially prediction based on
76// the average is used, that gets overridden by the stddev prediction at
77// the end.
78TEST_VM(G1Predictions, average_stdev_predictions) {
79 G1Predictions predictor(0.5);
80 TruncatedSeq s;
81
82 s.add(0.5);
83 double p1 = predictor.get_new_prediction(&s);
84 ASSERT_GT(p1, s.davg()) << "First prediction must be greater than average";
85
86 s.add(0.2);
87 double p2 = predictor.get_new_prediction(&s);
88 ASSERT_GT(p1, p2) << "First prediction must be greater than second";
89
90 s.add(0.5);
91 double p3 = predictor.get_new_prediction(&s);
92 ASSERT_GT(p2, p3) << "Second prediction must be greater than third";
93
94 s.add(0.2);
95 s.add(2.0);
96 double p4 = predictor.get_new_prediction(&s);
97 ASSERT_GT(p4, p3) << "Fourth prediction must be greater than third";
98}
99