Ichthyostega
20f3252892
Yet another chainsaw massacre. One of the most obnoxious annoyances with C++ metaprogramming is the need to insert `typename` and `template` qualifiers into most definitions, to help the compiler to cope with the syntax, which is not context-free. The recent standards adds several clarifications, so that most of these qualifiers are redundant now, at least at places where it is unambiguously clear that only a type can be given. GCC already supports most of these relaxing rules (Clang unfortunately lags way behind with support of newer language features...)
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 = 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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