// Initialize algorithm
GaMultithreadingAlgorithm::GaMultithreadingAlgorithm(const GaMultithreadingAlgorithmParams& parameters) : _parametersChange(false),
_workerIdCounter(0)
{
_numberOfThreads = parameters.GetNumberOfWorkers() + 1;
// make thread pool
_threads = new GaThread*[ _numberOfThreads ];
// defalut thread parameters
GaThreadParameter p;
p._functionParameters = this;
// initialize control and worker threads
for( int i = 0; i < _numberOfThreads; i++ )
{
p._functionPointer = !i ? ControlFlowWrapper : WorkFlowWrapper;
_threads[ i ] = new GaThread( p, false );
}
// initialize of semaphores for synchronization of worker threads
MakeSemaphore( _workerForkSync, _numberOfThreads - 1, 0 );
MakeSemaphore( _workerJoinSync, _numberOfThreads - 1, 0 );
MakeEvent( _controlSync, 0 );
}
RageSemaphore::RageSemaphore( CString sName, int iInitialValue ):
m_sName( sName )
{
m_pSema = MakeSemaphore( iInitialValue );
}
// Sets new parameters for algorithm
void GaMultithreadingAlgorithm::SetAlgorithmParameters(const GaAlgorithmParams& parameters)
{
int newCount = ( (const GaMultithreadingAlgorithmParams&)parameters ).GetNumberOfWorkers();
// state of algorithm couldnot be changed during parameter change
BlockStateChange();
int oldCount = _numberOfThreads - 1;
// nothing changed?
if( oldCount == newCount )
{
// now it safe to change state of algorithm
ReleaseStateChange();
return;
}
// if algorithm is running - stop all worker threads
if( _state == GAS_RUNNING )
{
_parametersChange = true;
// release working threads
_workersThreadOut = _workersThreadIn = oldCount;
UnlockSemaphore( _workerForkSync, oldCount );
// wait for working threads to be closed
for( int i = 1; i <= oldCount; i++ )
_threads[ i ]->Join();
_parametersChange = false;
}
// remove synchronization objects
DeleteSemaphore( _workerForkSync );
DeleteSemaphore( _workerJoinSync );
// make new synchronization object
MakeSemaphore( _workerForkSync, newCount, 0 );
MakeSemaphore( _workerJoinSync, newCount, 0 );
// new thread pool
GaThread** newThreads = new GaThread*[ newCount + 1 ];
// copy old needed threads
int lim = min( oldCount, newCount ) + 1;
for( int i = 0; i < lim; i++ )
newThreads[ i ] = _threads[ i ];
if( oldCount < newCount )
{
// new threads should be added
// new worker threads' parameters
GaThreadParameter p;
p._functionPointer = WorkFlowWrapper;
p._functionParameters = this;
// make new threads
for( int i = newCount - oldCount + 1; i < newCount; i++ )
newThreads[ i ] = new GaThread( p, false );
}
else
{
// threads should be remove
// free old threads
for( int i = oldCount - newCount + 1; i < oldCount; i++ )
delete _threads[ i ];
}
// swap pool of threads
delete[] _threads;
_threads = newThreads;
_numberOfThreads = newCount + 1;
// restart working threads if they were running
if( _state == GAS_RUNNING )
{
for( int i = 1; i <= newCount; i++ )
_threads[ i ]->Start();
}
// now it safe to change state of algorithm
ReleaseStateChange();
}
