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.
141 lines
4.1 KiB
C++
141 lines
4.1 KiB
C++
/*
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SyncLocking(Test) - check the monitor object based locking
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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 sync-locking-test.cpp
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** unit test \ref SyncLocking_test
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*/
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#include "lib/test/run.hpp"
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#include "lib/sync.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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using test::Test;
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using lib::explore;
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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_literals::operator ""us;
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namespace lib {
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namespace test{
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namespace { // private test classes and data...
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const uint NUM_THREADS = 200;
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const uint MAX_RAND_SUMMAND = 100;
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/** Helper to verify a contended chain calculation */
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template<class POLICY>
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class Checker
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: public Sync<POLICY>
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{
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size_t hot_sum_{0};
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size_t control_sum_{0};
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using Lock = typename Sync<POLICY>::Lock;
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public:
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bool
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verify() ///< verify test values got handled and accounted
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{
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Lock guard{this};
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return 0 < hot_sum_
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and control_sum_ == hot_sum_;
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}
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uint
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createVal() ///< generating test values, remembering the control sum
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{
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uint val = rani (MAX_RAND_SUMMAND);
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control_sum_ += val;
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return val;
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}
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void
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addValues (uint a, uint b) ///< to be called concurrently
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{
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Lock guard{this};
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hot_sum_ *= 2;
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sleep_for (200us); // force preemption
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hot_sum_ += 2 * (a+b);
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sleep_for (200us);
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hot_sum_ /= 2;
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}
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};
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}// (End) test classes and data....
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/******************************************************************//**
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* @test verify the object monitor provides locking and to prevent
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* data corruption on concurrent modification of shared storage.
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* - use a chained calculation with deliberate sleep state
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* while holding onto an intermediary result
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* - run this calculation contended by a huge number of threads
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* - either use locking or no locking
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* @see sync.happ
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* @see thread.hpp
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*/
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class SyncLocking_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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CHECK (can_calc_without_Error<NonrecursiveLock_NoWait>());
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CHECK (can_calc_without_Error<RecursiveLock_NoWait>());
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CHECK (not can_calc_without_Error<sync::NoLocking>());
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}
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template<class POLICY>
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bool
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can_calc_without_Error()
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{
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Checker<POLICY> checksum; // shared variable used by multiple threads
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lib::ScopedCollection<Thread> threads{NUM_THREADS};
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for (uint i=1; i<=NUM_THREADS; ++i)
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threads.emplace ([&checksum, // Note: added values prepared in main thread
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a = checksum.createVal(),
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b = checksum.createVal()]
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{
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checksum.addValues (a,b);
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});
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while (explore(threads).has_any())
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yield(); // wait for all threads to terminate
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return checksum.verify();
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}
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};
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/** Register this test class... */
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LAUNCHER (SyncLocking_test, "function common");
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}} // namespace lib::test
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