Ichthyostega
806db414dd
* Lumiera source code always was copyrighted by individual contributors * there is no entity "Lumiera.org" which holds any copyrights * Lumiera source code is provided under the GPL Version 2+ == Explanations == Lumiera as a whole is distributed under Copyleft, GNU General Public License Version 2 or above. For this to become legally effective, the ''File COPYING in the root directory is sufficient.'' The licensing header in each file is not strictly necessary, yet considered good practice; attaching a licence notice increases the likeliness that this information is retained in case someone extracts individual code files. However, it is not by the presence of some text, that legally binding licensing terms become effective; rather the fact matters that a given piece of code was provably copyrighted and published under a license. Even reformatting the code, renaming some variables or deleting parts of the code will not alter this legal situation, but rather creates a derivative work, which is likewise covered by the GPL! The most relevant information in the file header is the notice regarding the time of the first individual copyright claim. By virtue of this initial copyright, the first author is entitled to choose the terms of licensing. All further modifications are permitted and covered by the License. The specific wording or format of the copyright header is not legally relevant, as long as the intention to publish under the GPL remains clear. The extended wording was based on a recommendation by the FSF. It can be shortened, because the full terms of the license are provided alongside the distribution, in the file COPYING.
146 lines
5.3 KiB
C++
146 lines
5.3 KiB
C++
/*
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ThreadWrapper(Test) - starting threads and passing context
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Copyright (C)
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2008, Hermann Vosseler <Ichthyostega@web.de>
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**Lumiera** is free software; you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by the
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Free Software Foundation; either version 2 of the License, or (at your
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option) any later version. See the file COPYING for further details.
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* *****************************************************************/
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/** @file thread-wrapper-test.cpp
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** unit test \ref ThreadWrapper_test
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*/
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#include "lib/test/run.hpp"
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#include "lib/thread.hpp"
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#include "lib/iter-explorer.hpp"
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#include "lib/scoped-collection.hpp"
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#include "lib/test/microbenchmark.hpp"
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#include <atomic>
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#include <chrono>
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using test::Test;
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using lib::explore;
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using std::atomic_uint;
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using std::this_thread::yield;
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using std::this_thread::sleep_for;
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using std::chrono::microseconds;
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namespace lib {
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namespace test{
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namespace { // test parameters
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const uint NUM_THREADS = 200;
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const uint REPETITIONS = 10;
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}
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/*******************************************************************//**
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* @test use the lib::Thread wrapper for simplified definition of the
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* thread-function, argument binding and starting of threads.
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* @see thread.hpp
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* @see ThreadWrapperJoin_test
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* @see SyncLocking_test
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*/
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class ThreadWrapper_test : public Test
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{
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virtual void
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run (Arg)
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{
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seedRand();
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demonstrateSimpleUsage();
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verifyConcurrentExecution();
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}
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/** @test demonstrate simple usage of the thread-wrapper a λ-binding */
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void
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demonstrateSimpleUsage()
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{
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atomic_uint i{0};
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Thread thread("counter", [&]{ ++i; }); // bind a λ and launch thread
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while (thread) yield(); // ensure thread has finished and detached
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CHECK (i == 1); // verify the effect has taken place
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}
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/**
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* @test verify the thread function is actually performed concurrently
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* - use a derived Thread object, also holding a local data field
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* - the thread function sleeps, and then stores the sum of two numbers
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* - demonstrate that each instance can have a different argument binding
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* - verify each thread function has actually been invoked once per thread,
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* by comparing a local sum with values collected from the Thread objects,
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* - moreover measure the overall time required for launching the threads
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* and then waiting for all threads to have terminated and detached;
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* this time must be _shorter_ than all the _average_ sleep times
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* compounded (as if the function was invoked sequentially).
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*/
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void
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verifyConcurrentExecution()
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{
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struct TestThread
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: Thread
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{
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using Thread::Thread;
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uint local{0};
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void
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doIt (uint a, uint b) ///< the actual operation running in a separate thread
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{
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uint sum = a + b;
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sleep_for (microseconds{sum}); // Note: explicit random delay before local store
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local = sum;
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}
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};
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// prepare Storage for these objects (not created yet)
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lib::ScopedCollection<TestThread> threads{NUM_THREADS};
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size_t checkSum = 0;
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size_t globalSum = 0;
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auto launchThreads = [&]
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{
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for (uint i=1; i<=NUM_THREADS; ++i)
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{
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uint x = rani(1000);
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globalSum += (i + x);
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threads.emplace (&TestThread::doIt, i, x);
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} // Note: bind to member function, copying arguments
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while (explore(threads).has_any())
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yield(); // wait for all threads to have detached
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for (auto& t : threads)
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{
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CHECK (0 < t.local);
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checkSum += t.local;
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}
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};
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double runTime = benchmarkTime (launchThreads, REPETITIONS);
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CHECK (checkSum == globalSum); // sum of precomputed random numbers matches sum from threads
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CHECK (runTime < NUM_THREADS * 1000/2); // random sleep time should be > 500ms on average
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}
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};
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/** Register this test class... */
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LAUNCHER (ThreadWrapper_test, "function common");
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}} // namespace lib::test
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