Merged in rmlarsen/eigen (pull request PR-178)

Eigen Tensor cost model part 2: Thread scheduling for standard evaluators and reductions.
This commit is contained in:
Benoit Steiner 2016-04-15 14:53:15 -07:00
commit eb669f989f
4 changed files with 99 additions and 97 deletions

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@ -10,9 +10,9 @@
#ifndef EIGEN_CXX11_TENSOR_TENSOR_COST_MODEL_H
#define EIGEN_CXX11_TENSOR_TENSOR_COST_MODEL_H
#if !defined(EIGEN_USE_GPU)
#define EIGEN_USE_COST_MODEL
#endif
//#if !defined(EIGEN_USE_GPU)
//#define EIGEN_USE_COST_MODEL
//#endif
namespace Eigen {

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@ -189,6 +189,11 @@ struct TensorEvaluator<const Derived, Device>
return loadConstant(m_data+index);
}
EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE TensorOpCost costPerCoeff(bool vectorized) const {
return TensorOpCost(sizeof(CoeffReturnType), 0, 0, vectorized,
internal::unpacket_traits<PacketReturnType>::size);
}
EIGEN_DEVICE_FUNC const Scalar* data() const { return m_data; }
protected:

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@ -59,9 +59,16 @@ class TensorExecutor<Expression, DefaultDevice, true>
{
const Index size = array_prod(evaluator.dimensions());
const int PacketSize = unpacket_traits<typename TensorEvaluator<Expression, DefaultDevice>::PacketReturnType>::size;
// Manually unroll this loop since compilers don't do it.
const Index UnrolledSize = (size / (4 * PacketSize)) * 4 * PacketSize;
for (Index i = 0; i < UnrolledSize; i += 4*PacketSize) {
evaluator.evalPacket(i);
evaluator.evalPacket(i+PacketSize);
evaluator.evalPacket(i+2*PacketSize);
evaluator.evalPacket(i+3*PacketSize);
}
const Index VectorizedSize = (size / PacketSize) * PacketSize;
for (Index i = 0; i < VectorizedSize; i += PacketSize) {
for (Index i = UnrolledSize; i < VectorizedSize; i += PacketSize) {
evaluator.evalPacket(i);
}
for (Index i = VectorizedSize; i < size; ++i) {
@ -78,8 +85,9 @@ class TensorExecutor<Expression, DefaultDevice, true>
#ifdef EIGEN_USE_THREADS
template <typename Evaluator, typename Index, bool Vectorizable>
struct EvalRange {
static void run(Evaluator evaluator, const Index first, const Index last) {
eigen_assert(last > first);
static void run(Evaluator* evaluator_in, const Index first, const Index last) {
Evaluator evaluator = *evaluator_in;
eigen_assert(last >= first);
for (Index i = first; i < last; ++i) {
evaluator.evalScalar(i);
}
@ -88,28 +96,34 @@ struct EvalRange {
template <typename Evaluator, typename Index>
struct EvalRange<Evaluator, Index, true> {
static void run(Evaluator evaluator, const Index first, const Index last) {
eigen_assert(last > first);
static void run(Evaluator* evaluator_in, const Index first, const Index last) {
Evaluator evaluator = *evaluator_in;
eigen_assert(last >= first);
Index i = first;
static const int PacketSize = unpacket_traits<typename Evaluator::PacketReturnType>::size;
const int PacketSize = unpacket_traits<typename Evaluator::PacketReturnType>::size;
if (last - first >= PacketSize) {
eigen_assert(first % PacketSize == 0);
Index lastPacket = last - (last % PacketSize);
for (; i < lastPacket; i += PacketSize) {
Index last_chunk_offset = last - 4 * PacketSize;
// Manually unroll this loop since compilers don't do it.
for (; i <= last_chunk_offset; i += 4*PacketSize) {
evaluator.evalPacket(i);
evaluator.evalPacket(i+PacketSize);
evaluator.evalPacket(i+2*PacketSize);
evaluator.evalPacket(i+3*PacketSize);
}
last_chunk_offset = last - PacketSize;
for (; i <= last_chunk_offset; i += PacketSize) {
evaluator.evalPacket(i);
}
}
for (; i < last; ++i) {
evaluator.evalScalar(i);
}
}
};
template<typename Expression, bool Vectorizable>
class TensorExecutor<Expression, ThreadPoolDevice, Vectorizable>
{
template <typename Expression, bool Vectorizable>
class TensorExecutor<Expression, ThreadPoolDevice, Vectorizable> {
public:
typedef typename Expression::Index Index;
static inline void run(const Expression& expr, const ThreadPoolDevice& device)
@ -119,24 +133,34 @@ class TensorExecutor<Expression, ThreadPoolDevice, Vectorizable>
const bool needs_assign = evaluator.evalSubExprsIfNeeded(NULL);
if (needs_assign)
{
const Index PacketSize = Vectorizable ? unpacket_traits<typename Evaluator::PacketReturnType>::size : 1;
const Index size = array_prod(evaluator.dimensions());
static const int PacketSize = Vectorizable ? unpacket_traits<typename Evaluator::PacketReturnType>::size : 1;
int blocksz = std::ceil<int>(static_cast<float>(size)/device.numThreads()) + PacketSize - 1;
const Index blocksize = numext::maxi<Index>(PacketSize, (blocksz - (blocksz % PacketSize)));
const unsigned int numblocks = static_cast<unsigned int>(size / blocksize);
Barrier barrier(numblocks);
for (unsigned int i = 0; i < numblocks; ++i) {
device.enqueue_with_barrier(&barrier, &EvalRange<Evaluator, Index, Vectorizable>::run, evaluator, i*blocksize, (i+1)*blocksize);
int num_threads = device.numThreads();
#ifdef EIGEN_USE_COST_MODEL
if (num_threads > 1) {
num_threads = TensorCostModel<ThreadPoolDevice>::numThreads(
size, evaluator.costPerCoeff(Vectorizable), num_threads);
}
#endif
if (num_threads == 1) {
EvalRange<Evaluator, Index, Vectorizable>::run(&evaluator, 0, size);
} else {
Index blocksz = std::ceil<Index>(static_cast<float>(size)/num_threads) + PacketSize - 1;
const Index blocksize = numext::maxi<Index>(PacketSize, (blocksz - (blocksz % PacketSize)));
const Index numblocks = size / blocksize;
if (static_cast<Index>(numblocks) * blocksize < size) {
EvalRange<Evaluator, Index, Vectorizable>::run(evaluator, numblocks * blocksize, size);
Barrier barrier(numblocks);
for (int i = 0; i < numblocks; ++i) {
device.enqueue_with_barrier(
&barrier, &EvalRange<Evaluator, Index, Vectorizable>::run,
&evaluator, i * blocksize, (i + 1) * blocksize);
}
if (numblocks * blocksize < size) {
EvalRange<Evaluator, Index, Vectorizable>::run(
&evaluator, numblocks * blocksize, size);
}
barrier.Wait();
}
barrier.Wait();
}
evaluator.cleanup();
}
@ -226,7 +250,6 @@ inline void TensorExecutor<Expression, GpuDevice, Vectorizable>::run(
#endif // __CUDACC__
#endif // EIGEN_USE_GPU
} // end namespace internal
} // end namespace Eigen

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@ -214,7 +214,7 @@ struct FullReducer {
static EIGEN_DEVICE_FUNC void run(const Self& self, Op& reducer, const Device&, typename Self::CoeffReturnType* output) {
const typename Self::Index num_coeffs = array_prod(self.m_impl.dimensions());
*output = InnerMostDimReducer<Self, Op>::reduce(self, 0, num_coeffs, reducer);
*output = InnerMostDimReducer<Self, Op, Vectorizable>::reduce(self, 0, num_coeffs, reducer);
}
};
@ -222,18 +222,19 @@ struct FullReducer {
#ifdef EIGEN_USE_THREADS
// Multithreaded full reducers
template <typename Self, typename Op,
bool vectorizable = (Self::InputPacketAccess & Op::PacketAccess)>
bool Vectorizable = (Self::InputPacketAccess & Op::PacketAccess)>
struct FullReducerShard {
static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void run(const Self& self, typename Self::Index firstIndex,
typename Self::Index numValuesToReduce, Op& reducer,
typename Self::CoeffReturnType* output) {
*output = InnerMostDimReducer<Self, Op, vectorizable>::reduce(
*output = InnerMostDimReducer<Self, Op, Vectorizable>::reduce(
self, firstIndex, numValuesToReduce, reducer);
}
};
template <typename Self, typename Op>
struct FullReducer<Self, Op, ThreadPoolDevice, false> {
// Multithreaded full reducer
template <typename Self, typename Op, bool Vectorizable>
struct FullReducer<Self, Op, ThreadPoolDevice, Vectorizable> {
static const bool HasOptimizedImplementation = !Op::IsStateful;
static const int PacketSize =
unpacket_traits<typename Self::PacketReturnType>::size;
@ -247,79 +248,44 @@ struct FullReducer<Self, Op, ThreadPoolDevice, false> {
*output = reducer.finalize(reducer.initialize());
return;
}
const std::size_t num_threads = device.numThreads();
#ifdef EIGEN_USE_COST_MODEL
const TensorOpCost cost =
self.m_impl.costPerCoeff(Vectorizable) +
TensorOpCost(0, 0, internal::functor_traits<Op>::Cost, Vectorizable,
PacketSize);
const int num_threads = TensorCostModel<ThreadPoolDevice>::numThreads(
num_coeffs, cost, device.numThreads());
#else
const int num_threads = device.numThreads();
#endif
if (num_threads == 1) {
*output = InnerMostDimReducer<Self, Op, false>::reduce(self, 0, num_coeffs, reducer);
return;
} else {
const Index blocksize = std::floor<Index>(static_cast<float>(num_coeffs) / num_threads);
const unsigned int numblocks = blocksize > 0 ? static_cast<unsigned int>(num_coeffs / blocksize) : 0;
eigen_assert(num_coeffs >= static_cast<Index>(numblocks) * blocksize);
Barrier barrier(numblocks);
MaxSizeVector<typename Self::CoeffReturnType> shards(numblocks, reducer.initialize());
for (unsigned int i = 0; i < numblocks; ++i) {
device.enqueue_with_barrier(&barrier, &FullReducerShard<Self, Op, false>::run, self,
i * blocksize, blocksize, reducer, &shards[i]);
}
typename Self::CoeffReturnType finalShard;
if (static_cast<Index>(numblocks) * blocksize < num_coeffs) {
finalShard = InnerMostDimReducer<Self, Op, false>::reduce(
self, numblocks * blocksize, num_coeffs - numblocks * blocksize, reducer);
} else {
finalShard = reducer.initialize();
}
barrier.Wait();
for (unsigned int i = 0; i < numblocks; ++i) {
reducer.reduce(shards[i], &finalShard);
}
*output = reducer.finalize(finalShard);
}
}
};
template <typename Self, typename Op>
struct FullReducer<Self, Op, ThreadPoolDevice, true> {
static const bool HasOptimizedImplementation = !Op::IsStateful;
static const int PacketSize =
unpacket_traits<typename Self::PacketReturnType>::size;
// launch one reducer per thread and accumulate the result.
static void run(const Self& self, Op& reducer, const ThreadPoolDevice& device,
typename Self::CoeffReturnType* output) {
typedef typename Self::Index Index;
const Index num_coeffs = array_prod(self.m_impl.dimensions());
if (num_coeffs == 0) {
*output = reducer.finalize(reducer.initialize());
*output =
InnerMostDimReducer<Self, Op, Vectorizable>::reduce(self, 0, num_coeffs, reducer);
return;
}
const std::size_t num_threads = device.numThreads();
if (num_threads == 1) {
*output = InnerMostDimReducer<Self, Op, true>::reduce(self, 0, num_coeffs, reducer);
return;
}
const Index blocksize = std::floor<Index>(static_cast<float>(num_coeffs) / num_threads);
const unsigned int numblocks = blocksize > 0 ? static_cast<unsigned int>(num_coeffs / blocksize) : 0;
eigen_assert(num_coeffs >= static_cast<Index>(numblocks) * blocksize);
const Index blocksize =
std::floor<Index>(static_cast<float>(num_coeffs) / num_threads);
const Index numblocks = blocksize > 0 ? num_coeffs / blocksize : 0;
eigen_assert(num_coeffs >= numblocks * blocksize);
Barrier barrier(numblocks);
MaxSizeVector<typename Self::CoeffReturnType> shards(numblocks, reducer.initialize());
for (unsigned int i = 0; i < numblocks; ++i) {
device.enqueue_with_barrier(&barrier, &FullReducerShard<Self, Op, true>::run,
for (Index i = 0; i < numblocks; ++i) {
device.enqueue_with_barrier(&barrier, &FullReducerShard<Self, Op, Vectorizable>::run,
self, i * blocksize, blocksize, reducer,
&shards[i]);
}
typename Self::CoeffReturnType finalShard;
if (static_cast<Index>(numblocks) * blocksize < num_coeffs) {
finalShard = InnerMostDimReducer<Self, Op, true>::reduce(
self, numblocks * blocksize, num_coeffs - numblocks * blocksize, reducer);
if (numblocks * blocksize < num_coeffs) {
finalShard = InnerMostDimReducer<Self, Op, Vectorizable>::reduce(
self, numblocks * blocksize, num_coeffs - numblocks * blocksize,
reducer);
} else {
finalShard = reducer.initialize();
}
barrier.Wait();
for (unsigned int i = 0; i < numblocks; ++i) {
for (Index i = 0; i < numblocks; ++i) {
reducer.reduce(shards[i], &finalShard);
}
*output = reducer.finalize(finalShard);
@ -498,13 +464,21 @@ struct TensorEvaluator<const TensorReductionOp<Op, Dims, ArgType>, Device>
EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const Dimensions& dimensions() const { return m_dimensions; }
static bool size_large_enough(Index total_size) {
#ifndef EIGEN_USE_COST_MODEL
return total_size > 1024 * 1024;
#else
return true || total_size;
#endif
}
EIGEN_STRONG_INLINE EIGEN_DEVICE_FUNC bool evalSubExprsIfNeeded(CoeffReturnType* data) {
m_impl.evalSubExprsIfNeeded(NULL);
// Use the FullReducer if possible.
if (RunningFullReduction && internal::FullReducer<Self, Op, Device>::HasOptimizedImplementation &&
((RunningOnGPU && (m_device.majorDeviceVersion() >= 3)) ||
(!RunningOnGPU && (internal::array_prod(m_impl.dimensions()) > 1024 * 1024)))) {
(!RunningOnGPU && size_large_enough(internal::array_prod(m_impl.dimensions()))))) {
bool need_assign = false;
if (!data) {