test_os.cpp revision 13211:e1bb3d3d7ee2 
1/*
2 * Copyright (c) 2016, 2017, 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#include "precompiled.hpp"
25#include "runtime/os.hpp"
26#include "unittest.hpp"
27
28static size_t small_page_size() {
29  return os::vm_page_size();
30}
31
32static size_t large_page_size() {
33  const size_t large_page_size_example = 4 * M;
34  return os::page_size_for_region_aligned(large_page_size_example, 1);
35}
36
37TEST_VM(os, page_size_for_region) {
38  size_t large_page_example = 4 * M;
39  size_t large_page = os::page_size_for_region_aligned(large_page_example, 1);
40
41  size_t small_page = os::vm_page_size();
42  if (large_page > small_page) {
43    size_t num_small_in_large = large_page / small_page;
44    size_t page = os::page_size_for_region_aligned(large_page, num_small_in_large);
45    ASSERT_EQ(page, small_page) << "Did not get a small page";
46  }
47}
48
49TEST_VM(os, page_size_for_region_aligned) {
50  if (UseLargePages) {
51    const size_t small_page = small_page_size();
52    const size_t large_page = large_page_size();
53
54    if (large_page > small_page) {
55      size_t num_small_pages_in_large = large_page / small_page;
56      size_t page = os::page_size_for_region_aligned(large_page, num_small_pages_in_large);
57
58      ASSERT_EQ(page, small_page);
59    }
60  }
61}
62
63TEST_VM(os, page_size_for_region_alignment) {
64  if (UseLargePages) {
65    const size_t small_page = small_page_size();
66    const size_t large_page = large_page_size();
67    if (large_page > small_page) {
68      const size_t unaligned_region = large_page + 17;
69      size_t page = os::page_size_for_region_aligned(unaligned_region, 1);
70      ASSERT_EQ(page, small_page);
71
72      const size_t num_pages = 5;
73      const size_t aligned_region = large_page * num_pages;
74      page = os::page_size_for_region_aligned(aligned_region, num_pages);
75      ASSERT_EQ(page, large_page);
76    }
77  }
78}
79
80TEST_VM(os, page_size_for_region_unaligned) {
81  if (UseLargePages) {
82    // Given exact page size, should return that page size.
83    for (size_t i = 0; os::_page_sizes[i] != 0; i++) {
84      size_t expected = os::_page_sizes[i];
85      size_t actual = os::page_size_for_region_unaligned(expected, 1);
86      ASSERT_EQ(expected, actual);
87    }
88
89    // Given slightly larger size than a page size, return the page size.
90    for (size_t i = 0; os::_page_sizes[i] != 0; i++) {
91      size_t expected = os::_page_sizes[i];
92      size_t actual = os::page_size_for_region_unaligned(expected + 17, 1);
93      ASSERT_EQ(expected, actual);
94    }
95
96    // Given a slightly smaller size than a page size,
97    // return the next smaller page size.
98    if (os::_page_sizes[1] > os::_page_sizes[0]) {
99      size_t expected = os::_page_sizes[0];
100      size_t actual = os::page_size_for_region_unaligned(os::_page_sizes[1] - 17, 1);
101      ASSERT_EQ(actual, expected);
102    }
103
104    // Return small page size for values less than a small page.
105    size_t small_page = small_page_size();
106    size_t actual = os::page_size_for_region_unaligned(small_page - 17, 1);
107    ASSERT_EQ(small_page, actual);
108  }
109}
110
111TEST(os, test_random) {
112  const double m = 2147483647;
113  double mean = 0.0, variance = 0.0, t;
114  const int reps = 10000;
115  unsigned int seed = 1;
116
117  // tty->print_cr("seed %ld for %ld repeats...", seed, reps);
118  os::init_random(seed);
119  int num;
120  for (int k = 0; k < reps; k++) {
121    num = os::random();
122    double u = (double)num / m;
123    ASSERT_TRUE(u >= 0.0 && u <= 1.0) << "bad random number!";
124
125    // calculate mean and variance of the random sequence
126    mean += u;
127    variance += (u*u);
128  }
129  mean /= reps;
130  variance /= (reps - 1);
131
132  ASSERT_EQ(num, 1043618065) << "bad seed";
133  // tty->print_cr("mean of the 1st 10000 numbers: %f", mean);
134  int intmean = mean*100;
135  ASSERT_EQ(intmean, 50);
136  // tty->print_cr("variance of the 1st 10000 numbers: %f", variance);
137  int intvariance = variance*100;
138  ASSERT_EQ(intvariance, 33);
139  const double eps = 0.0001;
140  t = fabsd(mean - 0.5018);
141  ASSERT_LT(t, eps) << "bad mean";
142  t = (variance - 0.3355) < 0.0 ? -(variance - 0.3355) : variance - 0.3355;
143  ASSERT_LT(t, eps) << "bad variance";
144}
145
146
147#ifdef ASSERT
148TEST_VM_ASSERT_MSG(os, page_size_for_region_with_zero_min_pages, "sanity") {
149  size_t region_size = 16 * os::vm_page_size();
150  os::page_size_for_region_aligned(region_size, 0); // should assert
151}
152#endif
153