godot/thirdparty/bullet/LinearMath/TaskScheduler/btTaskScheduler.cpp

803 lines
25 KiB
C++

#include "LinearMath/btMinMax.h"
#include "LinearMath/btAlignedObjectArray.h"
#include "LinearMath/btThreads.h"
#include "LinearMath/btQuickprof.h"
#include <stdio.h>
#include <algorithm>
#if BT_THREADSAFE
#include "btThreadSupportInterface.h"
#if defined( _WIN32 )
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#endif
typedef unsigned long long btU64;
static const int kCacheLineSize = 64;
void btSpinPause()
{
#if defined( _WIN32 )
YieldProcessor();
#endif
}
struct WorkerThreadStatus
{
enum Type
{
kInvalid,
kWaitingForWork,
kWorking,
kSleeping,
};
};
ATTRIBUTE_ALIGNED64(class) WorkerThreadDirectives
{
static const int kMaxThreadCount = BT_MAX_THREAD_COUNT;
// directives for all worker threads packed into a single cacheline
char m_threadDirs[kMaxThreadCount];
public:
enum Type
{
kInvalid,
kGoToSleep, // go to sleep
kStayAwakeButIdle, // wait for not checking job queue
kScanForJobs, // actively scan job queue for jobs
};
WorkerThreadDirectives()
{
for ( int i = 0; i < kMaxThreadCount; ++i )
{
m_threadDirs[ i ] = 0;
}
}
Type getDirective(int threadId)
{
btAssert(threadId < kMaxThreadCount);
return static_cast<Type>(m_threadDirs[threadId]);
}
void setDirectiveByRange(int threadBegin, int threadEnd, Type dir)
{
btAssert( threadBegin < threadEnd );
btAssert( threadEnd <= kMaxThreadCount );
char dirChar = static_cast<char>(dir);
for ( int i = threadBegin; i < threadEnd; ++i )
{
m_threadDirs[ i ] = dirChar;
}
}
};
class JobQueue;
ATTRIBUTE_ALIGNED64(struct) ThreadLocalStorage
{
int m_threadId;
WorkerThreadStatus::Type m_status;
int m_numJobsFinished;
btSpinMutex m_mutex;
btScalar m_sumResult;
WorkerThreadDirectives * m_directive;
JobQueue* m_queue;
btClock* m_clock;
unsigned int m_cooldownTime;
};
struct IJob
{
virtual void executeJob(int threadId) = 0;
};
class ParallelForJob : public IJob
{
const btIParallelForBody* m_body;
int m_begin;
int m_end;
public:
ParallelForJob( int iBegin, int iEnd, const btIParallelForBody& body )
{
m_body = &body;
m_begin = iBegin;
m_end = iEnd;
}
virtual void executeJob(int threadId) BT_OVERRIDE
{
BT_PROFILE( "executeJob" );
// call the functor body to do the work
m_body->forLoop( m_begin, m_end );
}
};
class ParallelSumJob : public IJob
{
const btIParallelSumBody* m_body;
ThreadLocalStorage* m_threadLocalStoreArray;
int m_begin;
int m_end;
public:
ParallelSumJob( int iBegin, int iEnd, const btIParallelSumBody& body, ThreadLocalStorage* tls )
{
m_body = &body;
m_threadLocalStoreArray = tls;
m_begin = iBegin;
m_end = iEnd;
}
virtual void executeJob( int threadId ) BT_OVERRIDE
{
BT_PROFILE( "executeJob" );
// call the functor body to do the work
btScalar val = m_body->sumLoop( m_begin, m_end );
#if BT_PARALLEL_SUM_DETERMINISTISM
// by truncating bits of the result, we can make the parallelSum deterministic (at the expense of precision)
const float TRUNC_SCALE = float(1<<19);
val = floor(val*TRUNC_SCALE+0.5f)/TRUNC_SCALE; // truncate some bits
#endif
m_threadLocalStoreArray[threadId].m_sumResult += val;
}
};
ATTRIBUTE_ALIGNED64(class) JobQueue
{
btThreadSupportInterface* m_threadSupport;
btCriticalSection* m_queueLock;
btSpinMutex m_mutex;
btAlignedObjectArray<IJob*> m_jobQueue;
char* m_jobMem;
int m_jobMemSize;
bool m_queueIsEmpty;
int m_tailIndex;
int m_headIndex;
int m_allocSize;
bool m_useSpinMutex;
btAlignedObjectArray<JobQueue*> m_neighborContexts;
char m_cachePadding[kCacheLineSize]; // prevent false sharing
void freeJobMem()
{
if ( m_jobMem )
{
// free old
btAlignedFree(m_jobMem);
m_jobMem = NULL;
}
}
void resizeJobMem(int newSize)
{
if (newSize > m_jobMemSize)
{
freeJobMem();
m_jobMem = static_cast<char*>(btAlignedAlloc(newSize, kCacheLineSize));
m_jobMemSize = newSize;
}
}
public:
JobQueue()
{
m_jobMem = NULL;
m_jobMemSize = 0;
m_threadSupport = NULL;
m_queueLock = NULL;
m_headIndex = 0;
m_tailIndex = 0;
m_useSpinMutex = false;
}
~JobQueue()
{
exit();
}
void exit()
{
freeJobMem();
if (m_queueLock && m_threadSupport)
{
m_threadSupport->deleteCriticalSection(m_queueLock);
m_queueLock = NULL;
m_threadSupport = 0;
}
}
void init(btThreadSupportInterface* threadSup, btAlignedObjectArray<JobQueue>* contextArray)
{
m_threadSupport = threadSup;
if (threadSup)
{
m_queueLock = m_threadSupport->createCriticalSection();
}
setupJobStealing(contextArray, contextArray->size());
}
void setupJobStealing(btAlignedObjectArray<JobQueue>* contextArray, int numActiveContexts)
{
btAlignedObjectArray<JobQueue>& contexts = *contextArray;
int selfIndex = 0;
for (int i = 0; i < contexts.size(); ++i)
{
if ( this == &contexts[ i ] )
{
selfIndex = i;
break;
}
}
int numNeighbors = btMin(2, contexts.size() - 1);
int neighborOffsets[ ] = {-1, 1, -2, 2, -3, 3};
int numOffsets = sizeof(neighborOffsets)/sizeof(neighborOffsets[0]);
m_neighborContexts.reserve( numNeighbors );
m_neighborContexts.resizeNoInitialize(0);
for (int i = 0; i < numOffsets && m_neighborContexts.size() < numNeighbors; i++)
{
int neighborIndex = selfIndex + neighborOffsets[i];
if ( neighborIndex >= 0 && neighborIndex < numActiveContexts)
{
m_neighborContexts.push_back( &contexts[ neighborIndex ] );
}
}
}
bool isQueueEmpty() const {return m_queueIsEmpty;}
void lockQueue()
{
if ( m_useSpinMutex )
{
m_mutex.lock();
}
else
{
m_queueLock->lock();
}
}
void unlockQueue()
{
if ( m_useSpinMutex )
{
m_mutex.unlock();
}
else
{
m_queueLock->unlock();
}
}
void clearQueue(int jobCount, int jobSize)
{
lockQueue();
m_headIndex = 0;
m_tailIndex = 0;
m_allocSize = 0;
m_queueIsEmpty = true;
int jobBufSize = jobSize * jobCount;
// make sure we have enough memory allocated to store jobs
if ( jobBufSize > m_jobMemSize )
{
resizeJobMem( jobBufSize );
}
// make sure job queue is big enough
if ( jobCount > m_jobQueue.capacity() )
{
m_jobQueue.reserve( jobCount );
}
unlockQueue();
m_jobQueue.resizeNoInitialize( 0 );
}
void* allocJobMem(int jobSize)
{
btAssert(m_jobMemSize >= (m_allocSize + jobSize));
void* jobMem = &m_jobMem[m_allocSize];
m_allocSize += jobSize;
return jobMem;
}
void submitJob( IJob* job )
{
btAssert( reinterpret_cast<char*>( job ) >= &m_jobMem[ 0 ] && reinterpret_cast<char*>( job ) < &m_jobMem[ 0 ] + m_allocSize );
m_jobQueue.push_back( job );
lockQueue();
m_tailIndex++;
m_queueIsEmpty = false;
unlockQueue();
}
IJob* consumeJobFromOwnQueue()
{
if ( m_queueIsEmpty )
{
// lock free path. even if this is taken erroneously it isn't harmful
return NULL;
}
IJob* job = NULL;
lockQueue();
if ( !m_queueIsEmpty )
{
job = m_jobQueue[ m_headIndex++ ];
btAssert( reinterpret_cast<char*>( job ) >= &m_jobMem[ 0 ] && reinterpret_cast<char*>( job ) < &m_jobMem[ 0 ] + m_allocSize );
if ( m_headIndex == m_tailIndex )
{
m_queueIsEmpty = true;
}
}
unlockQueue();
return job;
}
IJob* consumeJob()
{
if (IJob* job = consumeJobFromOwnQueue())
{
return job;
}
// own queue is empty, try to steal from neighbor
for (int i = 0; i < m_neighborContexts.size(); ++i)
{
JobQueue* otherContext = m_neighborContexts[ i ];
if ( IJob* job = otherContext->consumeJobFromOwnQueue() )
{
return job;
}
}
return NULL;
}
};
static void WorkerThreadFunc( void* userPtr )
{
BT_PROFILE( "WorkerThreadFunc" );
ThreadLocalStorage* localStorage = (ThreadLocalStorage*) userPtr;
JobQueue* jobQueue = localStorage->m_queue;
bool shouldSleep = false;
int threadId = localStorage->m_threadId;
while (! shouldSleep)
{
// do work
localStorage->m_mutex.lock();
while ( IJob* job = jobQueue->consumeJob() )
{
localStorage->m_status = WorkerThreadStatus::kWorking;
job->executeJob( threadId );
localStorage->m_numJobsFinished++;
}
localStorage->m_status = WorkerThreadStatus::kWaitingForWork;
localStorage->m_mutex.unlock();
btU64 clockStart = localStorage->m_clock->getTimeMicroseconds();
// while queue is empty,
while (jobQueue->isQueueEmpty())
{
// todo: spin wait a bit to avoid hammering the empty queue
btSpinPause();
if ( localStorage->m_directive->getDirective(threadId) == WorkerThreadDirectives::kGoToSleep )
{
shouldSleep = true;
break;
}
// if jobs are incoming,
if ( localStorage->m_directive->getDirective( threadId ) == WorkerThreadDirectives::kScanForJobs )
{
clockStart = localStorage->m_clock->getTimeMicroseconds(); // reset clock
}
else
{
for ( int i = 0; i < 50; ++i )
{
btSpinPause();
btSpinPause();
btSpinPause();
btSpinPause();
if (localStorage->m_directive->getDirective( threadId ) == WorkerThreadDirectives::kScanForJobs || !jobQueue->isQueueEmpty())
{
break;
}
}
// if no jobs incoming and queue has been empty for the cooldown time, sleep
btU64 timeElapsed = localStorage->m_clock->getTimeMicroseconds() - clockStart;
if (timeElapsed > localStorage->m_cooldownTime)
{
shouldSleep = true;
break;
}
}
}
}
{
BT_PROFILE("sleep");
// go sleep
localStorage->m_mutex.lock();
localStorage->m_status = WorkerThreadStatus::kSleeping;
localStorage->m_mutex.unlock();
}
}
class btTaskSchedulerDefault : public btITaskScheduler
{
btThreadSupportInterface* m_threadSupport;
WorkerThreadDirectives* m_workerDirective;
btAlignedObjectArray<JobQueue> m_jobQueues;
btAlignedObjectArray<JobQueue*> m_perThreadJobQueues;
btAlignedObjectArray<ThreadLocalStorage> m_threadLocalStorage;
btSpinMutex m_antiNestingLock; // prevent nested parallel-for
btClock m_clock;
int m_numThreads;
int m_numWorkerThreads;
int m_numActiveJobQueues;
int m_maxNumThreads;
int m_numJobs;
static const int kFirstWorkerThreadId = 1;
public:
btTaskSchedulerDefault() : btITaskScheduler("ThreadSupport")
{
m_threadSupport = NULL;
m_workerDirective = NULL;
}
virtual ~btTaskSchedulerDefault()
{
waitForWorkersToSleep();
for ( int i = 0; i < m_jobQueues.size(); ++i )
{
m_jobQueues[i].exit();
}
if (m_threadSupport)
{
delete m_threadSupport;
m_threadSupport = NULL;
}
if (m_workerDirective)
{
btAlignedFree(m_workerDirective);
m_workerDirective = NULL;
}
}
void init()
{
btThreadSupportInterface::ConstructionInfo constructionInfo( "TaskScheduler", WorkerThreadFunc );
m_threadSupport = btThreadSupportInterface::create( constructionInfo );
m_workerDirective = static_cast<WorkerThreadDirectives*>(btAlignedAlloc(sizeof(*m_workerDirective), 64));
m_numWorkerThreads = m_threadSupport->getNumWorkerThreads();
m_maxNumThreads = m_threadSupport->getNumWorkerThreads() + 1;
m_numThreads = m_maxNumThreads;
// ideal to have one job queue for each physical processor (except for the main thread which needs no queue)
int numThreadsPerQueue = m_threadSupport->getLogicalToPhysicalCoreRatio();
int numJobQueues = (numThreadsPerQueue == 1) ? (m_maxNumThreads-1) : (m_maxNumThreads / numThreadsPerQueue);
m_jobQueues.resize(numJobQueues);
m_numActiveJobQueues = numJobQueues;
for ( int i = 0; i < m_jobQueues.size(); ++i )
{
m_jobQueues[i].init( m_threadSupport, &m_jobQueues );
}
m_perThreadJobQueues.resize(m_numThreads);
for ( int i = 0; i < m_numThreads; i++ )
{
JobQueue* jq = NULL;
// only worker threads get a job queue
if (i > 0)
{
if (numThreadsPerQueue == 1)
{
// one queue per worker thread
jq = &m_jobQueues[ i - kFirstWorkerThreadId ];
}
else
{
// 2 threads share each queue
jq = &m_jobQueues[ i / numThreadsPerQueue ];
}
}
m_perThreadJobQueues[i] = jq;
}
m_threadLocalStorage.resize(m_numThreads);
for ( int i = 0; i < m_numThreads; i++ )
{
ThreadLocalStorage& storage = m_threadLocalStorage[i];
storage.m_threadId = i;
storage.m_directive = m_workerDirective;
storage.m_status = WorkerThreadStatus::kSleeping;
storage.m_cooldownTime = 100; // 100 microseconds, threads go to sleep after this long if they have nothing to do
storage.m_clock = &m_clock;
storage.m_queue = m_perThreadJobQueues[i];
}
setWorkerDirectives( WorkerThreadDirectives::kGoToSleep ); // no work for them yet
setNumThreads( m_threadSupport->getCacheFriendlyNumThreads() );
}
void setWorkerDirectives(WorkerThreadDirectives::Type dir)
{
m_workerDirective->setDirectiveByRange(kFirstWorkerThreadId, m_numThreads, dir);
}
virtual int getMaxNumThreads() const BT_OVERRIDE
{
return m_maxNumThreads;
}
virtual int getNumThreads() const BT_OVERRIDE
{
return m_numThreads;
}
virtual void setNumThreads( int numThreads ) BT_OVERRIDE
{
m_numThreads = btMax( btMin(numThreads, int(m_maxNumThreads)), 1 );
m_numWorkerThreads = m_numThreads - 1;
m_numActiveJobQueues = 0;
// if there is at least 1 worker,
if ( m_numWorkerThreads > 0 )
{
// re-setup job stealing between queues to avoid attempting to steal from an inactive job queue
JobQueue* lastActiveContext = m_perThreadJobQueues[ m_numThreads - 1 ];
int iLastActiveContext = lastActiveContext - &m_jobQueues[0];
m_numActiveJobQueues = iLastActiveContext + 1;
for ( int i = 0; i < m_jobQueues.size(); ++i )
{
m_jobQueues[ i ].setupJobStealing( &m_jobQueues, m_numActiveJobQueues );
}
}
m_workerDirective->setDirectiveByRange(m_numThreads, BT_MAX_THREAD_COUNT, WorkerThreadDirectives::kGoToSleep);
}
void waitJobs()
{
BT_PROFILE( "waitJobs" );
// have the main thread work until the job queues are empty
int numMainThreadJobsFinished = 0;
for ( int i = 0; i < m_numActiveJobQueues; ++i )
{
while ( IJob* job = m_jobQueues[i].consumeJob() )
{
job->executeJob( 0 );
numMainThreadJobsFinished++;
}
}
// done with jobs for now, tell workers to rest (but not sleep)
setWorkerDirectives( WorkerThreadDirectives::kStayAwakeButIdle );
btU64 clockStart = m_clock.getTimeMicroseconds();
// wait for workers to finish any jobs in progress
while ( true )
{
int numWorkerJobsFinished = 0;
for ( int iThread = kFirstWorkerThreadId; iThread < m_numThreads; ++iThread )
{
ThreadLocalStorage* storage = &m_threadLocalStorage[iThread];
storage->m_mutex.lock();
numWorkerJobsFinished += storage->m_numJobsFinished;
storage->m_mutex.unlock();
}
if (numWorkerJobsFinished + numMainThreadJobsFinished == m_numJobs)
{
break;
}
btU64 timeElapsed = m_clock.getTimeMicroseconds() - clockStart;
btAssert(timeElapsed < 1000);
if (timeElapsed > 100000)
{
break;
}
btSpinPause();
}
}
void wakeWorkers(int numWorkersToWake)
{
BT_PROFILE( "wakeWorkers" );
btAssert( m_workerDirective->getDirective(1) == WorkerThreadDirectives::kScanForJobs );
int numDesiredWorkers = btMin(numWorkersToWake, m_numWorkerThreads);
int numActiveWorkers = 0;
for ( int iWorker = 0; iWorker < m_numWorkerThreads; ++iWorker )
{
// note this count of active workers is not necessarily totally reliable, because a worker thread could be
// just about to put itself to sleep. So we may on occasion fail to wake up all the workers. It should be rare.
ThreadLocalStorage& storage = m_threadLocalStorage[ kFirstWorkerThreadId + iWorker ];
if (storage.m_status != WorkerThreadStatus::kSleeping)
{
numActiveWorkers++;
}
}
for ( int iWorker = 0; iWorker < m_numWorkerThreads && numActiveWorkers < numDesiredWorkers; ++iWorker )
{
ThreadLocalStorage& storage = m_threadLocalStorage[ kFirstWorkerThreadId + iWorker ];
if (storage.m_status == WorkerThreadStatus::kSleeping)
{
m_threadSupport->runTask( iWorker, &storage );
numActiveWorkers++;
}
}
}
void waitForWorkersToSleep()
{
BT_PROFILE( "waitForWorkersToSleep" );
setWorkerDirectives( WorkerThreadDirectives::kGoToSleep );
m_threadSupport->waitForAllTasks();
for ( int i = kFirstWorkerThreadId; i < m_numThreads; i++ )
{
ThreadLocalStorage& storage = m_threadLocalStorage[i];
btAssert( storage.m_status == WorkerThreadStatus::kSleeping );
}
}
virtual void sleepWorkerThreadsHint() BT_OVERRIDE
{
BT_PROFILE( "sleepWorkerThreadsHint" );
// hint the task scheduler that we may not be using these threads for a little while
setWorkerDirectives( WorkerThreadDirectives::kGoToSleep );
}
void prepareWorkerThreads()
{
for ( int i = kFirstWorkerThreadId; i < m_numThreads; ++i )
{
ThreadLocalStorage& storage = m_threadLocalStorage[i];
storage.m_mutex.lock();
storage.m_numJobsFinished = 0;
storage.m_mutex.unlock();
}
setWorkerDirectives( WorkerThreadDirectives::kScanForJobs );
}
virtual void parallelFor( int iBegin, int iEnd, int grainSize, const btIParallelForBody& body ) BT_OVERRIDE
{
BT_PROFILE( "parallelFor_ThreadSupport" );
btAssert( iEnd >= iBegin );
btAssert( grainSize >= 1 );
int iterationCount = iEnd - iBegin;
if ( iterationCount > grainSize && m_numWorkerThreads > 0 && m_antiNestingLock.tryLock() )
{
typedef ParallelForJob JobType;
int jobCount = ( iterationCount + grainSize - 1 ) / grainSize;
m_numJobs = jobCount;
btAssert( jobCount >= 2 ); // need more than one job for multithreading
int jobSize = sizeof( JobType );
for (int i = 0; i < m_numActiveJobQueues; ++i)
{
m_jobQueues[i].clearQueue( jobCount, jobSize );
}
// prepare worker threads for incoming work
prepareWorkerThreads();
// submit all of the jobs
int iJob = 0;
int iThread = kFirstWorkerThreadId; // first worker thread
for ( int i = iBegin; i < iEnd; i += grainSize )
{
btAssert( iJob < jobCount );
int iE = btMin( i + grainSize, iEnd );
JobQueue* jq = m_perThreadJobQueues[ iThread ];
btAssert(jq);
btAssert((jq - &m_jobQueues[0]) < m_numActiveJobQueues);
void* jobMem = jq->allocJobMem(jobSize);
JobType* job = new ( jobMem ) ParallelForJob( i, iE, body ); // placement new
jq->submitJob( job );
iJob++;
iThread++;
if ( iThread >= m_numThreads )
{
iThread = kFirstWorkerThreadId; // first worker thread
}
}
wakeWorkers( jobCount - 1 );
// put the main thread to work on emptying the job queue and then wait for all workers to finish
waitJobs();
m_antiNestingLock.unlock();
}
else
{
BT_PROFILE( "parallelFor_mainThread" );
// just run on main thread
body.forLoop( iBegin, iEnd );
}
}
virtual btScalar parallelSum( int iBegin, int iEnd, int grainSize, const btIParallelSumBody& body ) BT_OVERRIDE
{
BT_PROFILE( "parallelSum_ThreadSupport" );
btAssert( iEnd >= iBegin );
btAssert( grainSize >= 1 );
int iterationCount = iEnd - iBegin;
if ( iterationCount > grainSize && m_numWorkerThreads > 0 && m_antiNestingLock.tryLock() )
{
typedef ParallelSumJob JobType;
int jobCount = ( iterationCount + grainSize - 1 ) / grainSize;
m_numJobs = jobCount;
btAssert( jobCount >= 2 ); // need more than one job for multithreading
int jobSize = sizeof( JobType );
for (int i = 0; i < m_numActiveJobQueues; ++i)
{
m_jobQueues[i].clearQueue( jobCount, jobSize );
}
// initialize summation
for ( int iThread = 0; iThread < m_numThreads; ++iThread )
{
m_threadLocalStorage[iThread].m_sumResult = btScalar(0);
}
// prepare worker threads for incoming work
prepareWorkerThreads();
// submit all of the jobs
int iJob = 0;
int iThread = kFirstWorkerThreadId; // first worker thread
for ( int i = iBegin; i < iEnd; i += grainSize )
{
btAssert( iJob < jobCount );
int iE = btMin( i + grainSize, iEnd );
JobQueue* jq = m_perThreadJobQueues[ iThread ];
btAssert(jq);
btAssert((jq - &m_jobQueues[0]) < m_numActiveJobQueues);
void* jobMem = jq->allocJobMem(jobSize);
JobType* job = new ( jobMem ) ParallelSumJob( i, iE, body, &m_threadLocalStorage[0] ); // placement new
jq->submitJob( job );
iJob++;
iThread++;
if ( iThread >= m_numThreads )
{
iThread = kFirstWorkerThreadId; // first worker thread
}
}
wakeWorkers( jobCount - 1 );
// put the main thread to work on emptying the job queue and then wait for all workers to finish
waitJobs();
// add up all the thread sums
btScalar sum = btScalar(0);
for ( int iThread = 0; iThread < m_numThreads; ++iThread )
{
sum += m_threadLocalStorage[ iThread ].m_sumResult;
}
m_antiNestingLock.unlock();
return sum;
}
else
{
BT_PROFILE( "parallelSum_mainThread" );
// just run on main thread
return body.sumLoop( iBegin, iEnd );
}
}
};
btITaskScheduler* btCreateDefaultTaskScheduler()
{
btTaskSchedulerDefault* ts = new btTaskSchedulerDefault();
ts->init();
return ts;
}
#else // #if BT_THREADSAFE
btITaskScheduler* btCreateDefaultTaskScheduler()
{
return NULL;
}
#endif // #else // #if BT_THREADSAFE