Multi-core Programming

Destroy the Castle Lab 4Code snippets

2

Lab 4 Activity 1 Steps 2-5 Declare ThreadContext structure

/////////////////////////////////////////////////////////////////////////////// Lab 4 Activity 1: Declare ThreadContext structure ////// ////// Declare a wrapper class for Win32 threads. Each instance's tick() ////// function copies thread local data and wakes up the thread by issuing ////// a SetEvent() call. ////// 1) As part of the lab, uncomment the macro definition for ////// THREADCONTEXT_EVENTS_DECLARED ////// 2) Add a declaration for the Thread handle (m_thread) ////// 3) Add declarations for the Start and Done event handles (m_evtStart ////// and m_evtDone) ////// ////// -------------------------- INSERT CODE HERE ------------------------ ///#define THREADCONTEXT_EVENTS_DECLARED

HANDLE m_evtStart;HANDLE m_evtDone;HANDLE m_thread;

3

Lab 4 Activity 1 Steps 6-7 Create and Init ThreadContext array

//////////////////////////////////////////////////////////////////////////////// ////// Lab 4 Activity 1: Create and Initialize ThreadContext array ////// ////// 1) Create an instance of the ThreadContext wrapper class for each of ////// the Win32 threads. ////// 2) 'init'ialize each ThreadContext structure ////// 3) Push a shared pointer to each ThreadContext onto the m_contexts ////// vector. ////// ------------------------- INSERT CODE HERE ------------------------- /// for (int i=0; i<num_threads; i++) {

ThreadContextPtr cp(new ThreadContext(this, i));

if (!cp->init())break;

m_contexts.push_back(cp); }

4

Lab 4 Activity 1 Step 8 Initialize ThreadContext

////////////////////////////////////////////////////////////////////////////// Lab 4 Activity 1: Initialize ThreadContext ////// ////// 1) Create Start and Done events used to signal the worker threads ////// 2) Create a Win32 Thread using _beginthreadex() with a 5K stack set ////// with entry point as _WorkerThreadProc ////// ////// ------------------------- INSERT CODE HERE ------------------------ ///

m_evtStart=::CreateEvent(0, FALSE, FALSE, 0 ); m_evtDone=::CreateEvent(0, FALSE, FALSE, 0 );

if (m_evtDone!=0 && m_evtStart!=0) { m_thread=(HANDLE)::_beginthreadex(NULL, 512*1024,

_WorkerThreadProc, this, 0, NULL );if (m_thread!=0 && m_thread!=INVALID_HANDLE_VALUE){

return true;}

}

5

Lab 4 Activity 2 Steps 1-4 Divide data and notify Worker threads

/////////////////////////////////////////////////////////////////////////////// Split the AI Workload to available threads and issue a SetEvent() to ////// let the worker threads start processing. This tick() function will ////// wait till the worker threads' tick() functions complete. ////// ////// 1) Split getNumMOBS() amount of work between 'threads'. ////// 2) Loop through and call the Workers' tick() functions using the ////// ThreadContext vector with the specified chunk of data. ////// 3) Finally, wait for all Worker threads to finish using a ////// WaitForMultipleObjects() call. ///

for (unsigned i=0; i<threads; i++){

unsigned from=i*blkSize;unsigned to=from+blkSize;

if (to>=getNumMOBS())to=getNumMOBS();

m_contexts[i]->tick(from, to, currentTime, elapsedTime );threadEvents[i]=m_contexts[i]->getDoneEvent();

}::WaitForMultipleObjects(threads, threadEvents, TRUE, INFINITE);

6

Lab 4 Activity 2 Steps 5-7 Implement Worker thread tick function

////////////////////////////////////////////////////////////////////////////// ////// Lab 4 Activity 2: Implement Worker thread function ////// ////// This function will wait till a Start event signal from the main AI ////// thread, and then call the DemoEngine's tick with the given slice of ////// data. ////// 1) Wait for m_evtStart event ////// 2) Check m_stopped to see if the AI DemoEngine is halted ////// 3) Issue the DemoEngine tick to handle the subset of data. ////// 4) SetEvent m_evtDone to let the main AIThread know we're done ////// ////// ------------------------- INSERT CODE HERE -------------------------///

::WaitForSingleObject(m_evtStart, INFINITE);if (m_stopped)

break;m_engine->tick(m_from, m_to, m_currentTime,m_elapsedTime);::SetEvent(m_evtDone);