1// This file is part of Eigen, a lightweight C++ template library
2// for linear algebra.
3//
4// Copyright (C) 2016 Dmitry Vyukov <dvyukov@google.com>
5// Copyright (C) 2016 Benoit Steiner <benoit.steiner.goog@gmail.com>
6//
7// This Source Code Form is subject to the terms of the Mozilla
8// Public License v. 2.0. If a copy of the MPL was not distributed
9// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
10
11#define EIGEN_USE_THREADS
12#include <cstdlib>
13#include "main.h"
14#include <Eigen/CXX11/ThreadPool>
15
16
17// Visual studio doesn't implement a rand_r() function since its
18// implementation of rand() is already thread safe
19int rand_reentrant(unsigned int* s) {
20#ifdef EIGEN_COMP_MSVC_STRICT
21  EIGEN_UNUSED_VARIABLE(s);
22  return rand();
23#else
24  return rand_r(s);
25#endif
26}
27
28void test_basic_runqueue()
29{
30  RunQueue<int, 4> q;
31  // Check empty state.
32  VERIFY(q.Empty());
33  VERIFY_IS_EQUAL(0u, q.Size());
34  VERIFY_IS_EQUAL(0, q.PopFront());
35  std::vector<int> stolen;
36  VERIFY_IS_EQUAL(0u, q.PopBackHalf(&stolen));
37  VERIFY_IS_EQUAL(0u, stolen.size());
38  // Push one front, pop one front.
39  VERIFY_IS_EQUAL(0, q.PushFront(1));
40  VERIFY_IS_EQUAL(1u, q.Size());
41  VERIFY_IS_EQUAL(1, q.PopFront());
42  VERIFY_IS_EQUAL(0u, q.Size());
43  // Push front to overflow.
44  VERIFY_IS_EQUAL(0, q.PushFront(2));
45  VERIFY_IS_EQUAL(1u, q.Size());
46  VERIFY_IS_EQUAL(0, q.PushFront(3));
47  VERIFY_IS_EQUAL(2u, q.Size());
48  VERIFY_IS_EQUAL(0, q.PushFront(4));
49  VERIFY_IS_EQUAL(3u, q.Size());
50  VERIFY_IS_EQUAL(0, q.PushFront(5));
51  VERIFY_IS_EQUAL(4u, q.Size());
52  VERIFY_IS_EQUAL(6, q.PushFront(6));
53  VERIFY_IS_EQUAL(4u, q.Size());
54  VERIFY_IS_EQUAL(5, q.PopFront());
55  VERIFY_IS_EQUAL(3u, q.Size());
56  VERIFY_IS_EQUAL(4, q.PopFront());
57  VERIFY_IS_EQUAL(2u, q.Size());
58  VERIFY_IS_EQUAL(3, q.PopFront());
59  VERIFY_IS_EQUAL(1u, q.Size());
60  VERIFY_IS_EQUAL(2, q.PopFront());
61  VERIFY_IS_EQUAL(0u, q.Size());
62  VERIFY_IS_EQUAL(0, q.PopFront());
63  // Push one back, pop one back.
64  VERIFY_IS_EQUAL(0, q.PushBack(7));
65  VERIFY_IS_EQUAL(1u, q.Size());
66  VERIFY_IS_EQUAL(1u, q.PopBackHalf(&stolen));
67  VERIFY_IS_EQUAL(1u, stolen.size());
68  VERIFY_IS_EQUAL(7, stolen[0]);
69  VERIFY_IS_EQUAL(0u, q.Size());
70  stolen.clear();
71  // Push back to overflow.
72  VERIFY_IS_EQUAL(0, q.PushBack(8));
73  VERIFY_IS_EQUAL(1u, q.Size());
74  VERIFY_IS_EQUAL(0, q.PushBack(9));
75  VERIFY_IS_EQUAL(2u, q.Size());
76  VERIFY_IS_EQUAL(0, q.PushBack(10));
77  VERIFY_IS_EQUAL(3u, q.Size());
78  VERIFY_IS_EQUAL(0, q.PushBack(11));
79  VERIFY_IS_EQUAL(4u, q.Size());
80  VERIFY_IS_EQUAL(12, q.PushBack(12));
81  VERIFY_IS_EQUAL(4u, q.Size());
82  // Pop back in halves.
83  VERIFY_IS_EQUAL(2u, q.PopBackHalf(&stolen));
84  VERIFY_IS_EQUAL(2u, stolen.size());
85  VERIFY_IS_EQUAL(10, stolen[0]);
86  VERIFY_IS_EQUAL(11, stolen[1]);
87  VERIFY_IS_EQUAL(2u, q.Size());
88  stolen.clear();
89  VERIFY_IS_EQUAL(1u, q.PopBackHalf(&stolen));
90  VERIFY_IS_EQUAL(1u, stolen.size());
91  VERIFY_IS_EQUAL(9, stolen[0]);
92  VERIFY_IS_EQUAL(1u, q.Size());
93  stolen.clear();
94  VERIFY_IS_EQUAL(1u, q.PopBackHalf(&stolen));
95  VERIFY_IS_EQUAL(1u, stolen.size());
96  VERIFY_IS_EQUAL(8, stolen[0]);
97  stolen.clear();
98  VERIFY_IS_EQUAL(0u, q.PopBackHalf(&stolen));
99  VERIFY_IS_EQUAL(0u, stolen.size());
100  // Empty again.
101  VERIFY(q.Empty());
102  VERIFY_IS_EQUAL(0u, q.Size());
103  VERIFY_IS_EQUAL(0, q.PushFront(1));
104  VERIFY_IS_EQUAL(0, q.PushFront(2));
105  VERIFY_IS_EQUAL(0, q.PushFront(3));
106  VERIFY_IS_EQUAL(1, q.PopBack());
107  VERIFY_IS_EQUAL(2, q.PopBack());
108  VERIFY_IS_EQUAL(3, q.PopBack());
109  VERIFY(q.Empty());
110  VERIFY_IS_EQUAL(0u, q.Size());
111}
112
113// Empty tests that the queue is not claimed to be empty when is is in fact not.
114// Emptiness property is crucial part of thread pool blocking scheme,
115// so we go to great effort to ensure this property. We create a queue with
116// 1 element and then push 1 element (either front or back at random) and pop
117// 1 element (either front or back at random). So queue always contains at least
118// 1 element, but otherwise changes chaotically. Another thread constantly tests
119// that the queue is not claimed to be empty.
120void test_empty_runqueue()
121{
122  RunQueue<int, 4> q;
123  q.PushFront(1);
124  std::atomic<bool> done(false);
125  std::thread mutator([&q, &done]() {
126    unsigned rnd = 0;
127    std::vector<int> stolen;
128    for (int i = 0; i < 1 << 18; i++) {
129      if (rand_reentrant(&rnd) % 2)
130        VERIFY_IS_EQUAL(0, q.PushFront(1));
131      else
132        VERIFY_IS_EQUAL(0, q.PushBack(1));
133      if (rand_reentrant(&rnd) % 2)
134        VERIFY_IS_EQUAL(1, q.PopFront());
135      else {
136        for (;;) {
137          if (q.PopBackHalf(&stolen) == 1) {
138            stolen.clear();
139            break;
140          }
141          VERIFY_IS_EQUAL(0u, stolen.size());
142        }
143      }
144    }
145    done = true;
146  });
147  while (!done) {
148    VERIFY(!q.Empty());
149    int size = q.Size();
150    VERIFY_GE(size, 1);
151    VERIFY_LE(size, 2);
152  }
153  VERIFY_IS_EQUAL(1, q.PopFront());
154  mutator.join();
155}
156
157// Stress is a chaotic random test.
158// One thread (owner) calls PushFront/PopFront, other threads call PushBack/
159// PopBack. Ensure that we don't crash, deadlock, and all sanity checks pass.
160void test_stress_runqueue()
161{
162  static const int kEvents = 1 << 18;
163  RunQueue<int, 8> q;
164  std::atomic<int> total(0);
165  std::vector<std::unique_ptr<std::thread>> threads;
166  threads.emplace_back(new std::thread([&q, &total]() {
167    int sum = 0;
168    int pushed = 1;
169    int popped = 1;
170    while (pushed < kEvents || popped < kEvents) {
171      if (pushed < kEvents) {
172        if (q.PushFront(pushed) == 0) {
173          sum += pushed;
174          pushed++;
175        }
176      }
177      if (popped < kEvents) {
178        int v = q.PopFront();
179        if (v != 0) {
180          sum -= v;
181          popped++;
182        }
183      }
184    }
185    total += sum;
186  }));
187  for (int i = 0; i < 2; i++) {
188    threads.emplace_back(new std::thread([&q, &total]() {
189      int sum = 0;
190      for (int j = 1; j < kEvents; j++) {
191        if (q.PushBack(j) == 0) {
192          sum += j;
193          continue;
194        }
195        EIGEN_THREAD_YIELD();
196        j--;
197      }
198      total += sum;
199    }));
200    threads.emplace_back(new std::thread([&q, &total]() {
201      int sum = 0;
202      std::vector<int> stolen;
203      for (int j = 1; j < kEvents;) {
204        if (q.PopBackHalf(&stolen) == 0) {
205          EIGEN_THREAD_YIELD();
206          continue;
207        }
208        while (stolen.size() && j < kEvents) {
209          int v = stolen.back();
210          stolen.pop_back();
211          VERIFY_IS_NOT_EQUAL(v, 0);
212          sum += v;
213          j++;
214        }
215      }
216      while (stolen.size()) {
217        int v = stolen.back();
218        stolen.pop_back();
219        VERIFY_IS_NOT_EQUAL(v, 0);
220        while ((v = q.PushBack(v)) != 0) EIGEN_THREAD_YIELD();
221      }
222      total -= sum;
223    }));
224  }
225  for (size_t i = 0; i < threads.size(); i++) threads[i]->join();
226  VERIFY(q.Empty());
227  VERIFY(total.load() == 0);
228}
229
230void test_cxx11_runqueue()
231{
232  CALL_SUBTEST_1(test_basic_runqueue());
233  CALL_SUBTEST_2(test_empty_runqueue());
234  CALL_SUBTEST_3(test_stress_runqueue());
235}
236