1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
|
// Copyright (c) 2020 Andrey Semashev
//
// Distributed under the Boost Software License, Version 1.0.
// See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
// This is a fuzzing test for waiting and notifying operations.
// The test creates a number of threads exceeding the number of hardware threads, each of which
// blocks on the atomic object. The main thread then notifies one or all threads repeatedly,
// while incrementing the atomic object. The test ends when the atomic counter reaches the predefined limit.
// The goal of the test is to verify that (a) it doesn't crash and (b) all threads get unblocked in the end.
#include <boost/memory_order.hpp>
#include <boost/atomic/atomic.hpp>
#include <iostream>
#include <boost/config.hpp>
#include <boost/bind/bind.hpp>
#include <boost/chrono/chrono.hpp>
#include <boost/thread/thread.hpp>
#include <boost/thread/barrier.hpp>
#include <boost/smart_ptr/scoped_array.hpp>
namespace chrono = boost::chrono;
boost::atomic< unsigned int > g_atomic(0u);
BOOST_CONSTEXPR_OR_CONST unsigned int loop_count = 4096u;
void thread_func(boost::barrier* barrier)
{
barrier->wait();
unsigned int old_count = 0u;
while (true)
{
unsigned int new_count = g_atomic.wait(old_count, boost::memory_order_relaxed);
if (new_count >= loop_count)
break;
old_count = new_count;
}
}
int main()
{
const unsigned int thread_count = boost::thread::hardware_concurrency() + 4u;
boost::barrier barrier(thread_count + 1u);
boost::scoped_array< boost::thread > threads(new boost::thread[thread_count]);
for (unsigned int i = 0u; i < thread_count; ++i)
boost::thread(boost::bind(&thread_func, &barrier)).swap(threads[i]);
barrier.wait();
// Let the threads block on the atomic counter
boost::this_thread::sleep_for(chrono::milliseconds(100));
while (true)
{
for (unsigned int i = 0u; i < thread_count; ++i)
{
g_atomic.opaque_add(1u, boost::memory_order_relaxed);
g_atomic.notify_one();
}
unsigned int old_count = g_atomic.fetch_add(1u, boost::memory_order_relaxed);
g_atomic.notify_all();
if ((old_count + 1u) >= loop_count)
break;
}
for (unsigned int i = 0u; i < thread_count; ++i)
threads[i].join();
return 0u;
}
|
