86 lines
2.6 KiB
C++
86 lines
2.6 KiB
C++
|
/**
|
||
|
|
* @file runner.cpp
|
||
|
|
* @author Sébastien Rouault <sebastien.rouault@epfl.ch>
|
||
|
|
*
|
||
|
|
* @section LICENSE
|
||
|
|
*
|
||
|
|
* Copyright © 2018-2019 Sébastien Rouault.
|
||
|
|
*
|
||
|
|
* This program is free software; you can redistribute it and/or modify
|
||
|
|
* it under the terms of the GNU General Public License as published by
|
||
|
|
* the Free Software Foundation; either version 3 of the License, or
|
||
|
|
* any later version. Please see https://gnu.org/licenses/gpl.html
|
||
|
|
*
|
||
|
|
* This program is distributed in the hope that it will be useful,
|
||
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||
|
|
* GNU General Public License for more details.
|
||
|
|
*
|
||
|
|
* @section DESCRIPTION
|
||
|
|
*
|
||
|
|
* Trivial program that call a function in several threads.
|
||
|
|
**/
|
||
|
|
|
||
|
|
// External headers
|
||
|
|
#include <atomic>
|
||
|
|
#include <iostream>
|
||
|
|
#include <thread>
|
||
|
|
|
||
|
|
// Internal headers
|
||
|
|
#include "entrypoint.hpp"
|
||
|
|
#include "runner.hpp"
|
||
|
|
|
||
|
|
// -------------------------------------------------------------------------- //
|
||
|
|
// Shared memory, access function and consistency check
|
||
|
|
|
||
|
|
static int counter = 0;
|
||
|
|
static ::std::atomic<int> check_counter{0};
|
||
|
|
|
||
|
|
/** Performs some operations on some shared memory.
|
||
|
|
**/
|
||
|
|
void shared_access() {
|
||
|
|
++counter;
|
||
|
|
check_counter.fetch_add(1, ::std::memory_order_relaxed);
|
||
|
|
}
|
||
|
|
|
||
|
|
/** (Empirically) checks that concurrent operations did not break consistency, warn accordingly.
|
||
|
|
**/
|
||
|
|
static void shared_check() {
|
||
|
|
auto calls = check_counter.load(::std::memory_order_relaxed);
|
||
|
|
if (counter == calls) {
|
||
|
|
::std::cout << "** No inconsistency detected (" << counter << " == " << calls << ") **" << ::std::endl;
|
||
|
|
} else {
|
||
|
|
::std::cout << "** Inconsistency detected (" << counter << " != " << calls << ") **" << ::std::endl;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// -------------------------------------------------------------------------- //
|
||
|
|
// Lock + thread launches and management
|
||
|
|
|
||
|
|
/** Program entry point.
|
||
|
|
* @param argc Arguments count
|
||
|
|
* @param argv Arguments values
|
||
|
|
* @return Program return code
|
||
|
|
**/
|
||
|
|
int main(int, char**) {
|
||
|
|
auto const nbworkers = []() {
|
||
|
|
auto res = ::std::thread::hardware_concurrency();
|
||
|
|
if (res == 0) {
|
||
|
|
::std::cout << "WARNING: unable to query '::std::thread::hardware_concurrency()', falling back to 4 threads" << ::std::endl;
|
||
|
|
res = 4;
|
||
|
|
}
|
||
|
|
return static_cast<size_t>(res);
|
||
|
|
}();
|
||
|
|
Lock lock;
|
||
|
|
::std::thread threads[nbworkers];
|
||
|
|
for (size_t i = 0; i < nbworkers; ++i) {
|
||
|
|
threads[i] = ::std::thread{[&](size_t i) {
|
||
|
|
entry_point(nbworkers, i, lock);
|
||
|
|
}, i};
|
||
|
|
}
|
||
|
|
for (auto&& thread: threads)
|
||
|
|
thread.join();
|
||
|
|
shared_check();
|
||
|
|
return 0;
|
||
|
|
}
|