libcruft-util/test/job/spinlock.cpp

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/*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* Copyright 2018 Danny Robson <danny@nerdcruft.net>
*/
#include "job/flag.hpp"
#include "job/spinlock.hpp"
#include "tap.hpp"
#include <thread>
#include <mutex>
///////////////////////////////////////////////////////////////////////////////
void
fight (util::job::flag &start, util::job::spinlock &l, int iterations)
{
start.wait ();
for (int count = 0; count < iterations; ++count)
std::lock_guard g (l);
};
//-----------------------------------------------------------------------------
int
main ()
{
util::TAP::logger tap;
util::job::spinlock l;
l.lock ();
tap.expect (true, "locked without contention");
l.unlock ();
tap.expect (true, "unlocked without contention");
if (std::thread::hardware_concurrency () < 2) {
tap.skip ("n-way fight");
} else {
constexpr int iterations = 1 << 12;
util::job::flag start_flag;
std::vector<std::thread> contestants;
for (unsigned i = 0; i < std::thread::hardware_concurrency (); ++i)
contestants.emplace_back (fight, std::ref (start_flag), std::ref (l), iterations);
start_flag.notify ();
for (auto &t: contestants)
t.join ();
tap.expect (true, "n-way fight, %! contestants", std::thread::hardware_concurrency ());
}
}