Ichthyostega
685be1b039
This is Step-2 : change the API towards application Notably all invocation variants to support member functions or a reference to bool flags are retracted, since today a λ-binding directly at usage site tends to be more readable. The function names are harmonised with the C++ standard and emergency shutdown in the Subsystem-Runner is rationalised. The old thread-wrapper test is repurposed to demonstrate the effectiveness of monitor based locking.
149 lines
4.4 KiB
C++
149 lines
4.4 KiB
C++
/*
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SyncLocking(Test) - check the monitor object based locking
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Copyright (C) Lumiera.org
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2008, Hermann Vosseler <Ichthyostega@web.de>
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License as
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published by the Free Software Foundation; either version 2 of
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the License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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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{rand() % 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_test2 : 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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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_test2, "function common");
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}} // namespace lib::test
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