Improvements to parallelFor.

Move some scalar functors from TensorFunctors. to Eigen core.
This commit is contained in:
Rasmus Munk Larsen 2016-05-12 14:07:22 -07:00
parent ae9688f313
commit e55deb21c5
6 changed files with 156 additions and 155 deletions

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@ -89,13 +89,13 @@ template<typename LhsScalar,typename RhsScalar> struct scalar_conj_product_op {
enum {
Conj = NumTraits<LhsScalar>::IsComplex
};
typedef typename scalar_product_traits<LhsScalar,RhsScalar>::ReturnType result_type;
EIGEN_EMPTY_STRUCT_CTOR(scalar_conj_product_op)
EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const result_type operator() (const LhsScalar& a, const RhsScalar& b) const
{ return conj_helper<LhsScalar,RhsScalar,Conj,false>().pmul(a,b); }
template<typename Packet>
EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const Packet packetOp(const Packet& a, const Packet& b) const
{ return conj_helper<Packet,Packet,Conj,false>().pmul(a,b); }
@ -591,6 +591,47 @@ template<typename Scalar>
struct functor_traits<scalar_inverse_mult_op<Scalar> >
{ enum { PacketAccess = packet_traits<Scalar>::HasDiv, Cost = NumTraits<Scalar>::template Div<PacketAccess>::Cost }; };
/** \internal
* \brief Template functor to compute the modulo between an array and a fixed scalar.
*/
template <typename Scalar>
struct scalar_mod_op {
EIGEN_DEVICE_FUNC scalar_mod_op(const Scalar& divisor) : m_divisor(divisor) {}
EIGEN_DEVICE_FUNC inline Scalar operator() (const Scalar& a) const { return a % m_divisor; }
const Scalar m_divisor;
};
template <typename Scalar>
struct functor_traits<scalar_mod_op<Scalar> >
{ enum { Cost = NumTraits<Scalar>::template Div<false>::Cost, PacketAccess = false }; };
/** \internal
* \brief Template functor to compute the modulo between two arrays.
*/
template <typename Scalar>
struct scalar_mod2_op {
EIGEN_EMPTY_STRUCT_CTOR(scalar_mod2_op);
EIGEN_DEVICE_FUNC inline Scalar operator() (const Scalar& a, const Scalar& b) const { return a % b; }
};
template <typename Scalar>
struct functor_traits<scalar_mod2_op<Scalar> >
{ enum { Cost = NumTraits<Scalar>::template Div<false>::Cost, PacketAccess = false }; };
/** \internal
* \brief Template functor to compute the float modulo between two arrays.
*/
template <typename Scalar>
struct scalar_fmod_op {
EIGEN_EMPTY_STRUCT_CTOR(scalar_fmod_op);
EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE Scalar
operator()(const Scalar& a, const Scalar& b) const {
return numext::fmod(a, b);
}
};
template <typename Scalar>
struct functor_traits<scalar_fmod_op<Scalar> > {
enum { Cost = 13, // Reciprocal throughput of FPREM on Haswell.
PacketAccess = false };
};
} // end namespace internal

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@ -496,7 +496,7 @@ struct functor_traits<scalar_digamma_op<Scalar> >
PacketAccess = packet_traits<Scalar>::HasDiGamma
};
};
/** \internal
* \brief Template functor to compute the Riemann Zeta function of two arguments.
* \sa class CwiseUnaryOp, Cwise::zeta()
@ -587,6 +587,33 @@ struct functor_traits<scalar_erfc_op<Scalar> >
};
};
/** \internal
* \brief Template functor to compute the sigmoid of a scalar
* \sa class CwiseUnaryOp, ArrayBase::sigmoid()
*/
template <typename T>
struct scalar_sigmoid_op {
EIGEN_EMPTY_STRUCT_CTOR(scalar_sigmoid_op)
EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE T operator()(const T& x) const {
const T one = T(1);
return one / (one + numext::exp(-x));
}
template <typename Packet> EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
Packet packetOp(const Packet& x) const {
const Packet one = pset1<Packet>(T(1));
return pdiv(one, padd(one, pexp(pnegate(x))));
}
};
template <typename T>
struct functor_traits<scalar_sigmoid_op<T> > {
enum {
Cost = NumTraits<T>::AddCost * 2 + NumTraits<T>::MulCost * 6,
PacketAccess = packet_traits<T>::HasAdd && packet_traits<T>::HasDiv &&
packet_traits<T>::HasNegate && packet_traits<T>::HasExp
};
};
/** \internal
* \brief Template functor to compute the atan of a scalar
@ -627,7 +654,7 @@ template<typename Scalar> struct scalar_tanh_op {
const Packet plus_9 = pset1<Packet>(9.0);
const Packet minus_9 = pset1<Packet>(-9.0);
const Packet x = pmax(minus_9, pmin(plus_9, _x));
// The monomial coefficients of the numerator polynomial (odd).
const Packet alpha_1 = pset1<Packet>(4.89352455891786e-03);
const Packet alpha_3 = pset1<Packet>(6.37261928875436e-04);
@ -636,16 +663,16 @@ template<typename Scalar> struct scalar_tanh_op {
const Packet alpha_9 = pset1<Packet>(-8.60467152213735e-11);
const Packet alpha_11 = pset1<Packet>(2.00018790482477e-13);
const Packet alpha_13 = pset1<Packet>(-2.76076847742355e-16);
// The monomial coefficients of the denominator polynomial (even).
const Packet beta_0 = pset1<Packet>(4.89352518554385e-03);
const Packet beta_2 = pset1<Packet>(2.26843463243900e-03);
const Packet beta_4 = pset1<Packet>(1.18534705686654e-04);
const Packet beta_6 = pset1<Packet>(1.19825839466702e-06);
// Since the polynomials are odd/even, we need x^2.
const Packet x2 = pmul(x, x);
// Evaluate the numerator polynomial p.
Packet p = pmadd(x2, alpha_13, alpha_11);
p = pmadd(x2, p, alpha_9);
@ -654,12 +681,12 @@ template<typename Scalar> struct scalar_tanh_op {
p = pmadd(x2, p, alpha_3);
p = pmadd(x2, p, alpha_1);
p = pmul(x, p);
// Evaluate the denominator polynomial p.
Packet q = pmadd(x2, beta_6, beta_4);
q = pmadd(x2, q, beta_2);
q = pmadd(x2, q, beta_0);
// Divide the numerator by the denominator.
return pdiv(p, q);
}
@ -938,7 +965,7 @@ struct scalar_sign_op<Scalar,true> {
template<typename Scalar>
struct functor_traits<scalar_sign_op<Scalar> >
{ enum {
Cost =
Cost =
NumTraits<Scalar>::IsComplex
? ( 8*NumTraits<Scalar>::MulCost ) // roughly
: ( 3*NumTraits<Scalar>::AddCost),

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@ -69,6 +69,7 @@ typedef unsigned __int64 uint64_t;
#include "src/Tensor/TensorMacros.h"
#include "src/Tensor/TensorForwardDeclarations.h"
#include "src/Tensor/TensorMeta.h"
#include "src/Tensor/TensorCostModel.h"
#include "src/Tensor/TensorDeviceDefault.h"
#include "src/Tensor/TensorDeviceThreadPool.h"
#include "src/Tensor/TensorDeviceCuda.h"
@ -83,7 +84,6 @@ typedef unsigned __int64 uint64_t;
#include "src/Tensor/TensorBase.h"
#include "src/Tensor/TensorCostModel.h"
#include "src/Tensor/TensorEvaluator.h"
#include "src/Tensor/TensorExpr.h"
#include "src/Tensor/TensorReduction.h"

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@ -172,67 +172,69 @@ struct ThreadPoolDevice {
pool_->Schedule(func);
}
// parallelFor executes f with [0, size) arguments in parallel and waits for
// completion. Block size is choosen between min_block_size and
// 2 * min_block_size to achieve the best parallel efficiency.
// If min_block_size == -1, parallelFor uses block size of 1.
// If hard_align > 0, block size is aligned to hard_align.
// If soft_align > hard_align, block size is aligned to soft_align provided
// that it does not increase block size too much.
void parallelFor(Index size, Index min_block_size, Index hard_align,
Index soft_align,
// parallelFor executes f with [0, n) arguments in parallel and waits for
// completion. F accepts a half-open interval [first, last).
// Block size is choosen based on the iteration cost and resulting parallel
// efficiency. If block_align is not nullptr, it is called to round up the
// block size.
void parallelFor(Index n, const TensorOpCost& cost,
std::function<Index(Index)> block_align,
std::function<void(Index, Index)> f) const {
if (size <= 1 || (min_block_size != -1 && size < min_block_size) ||
numThreads() == 1) {
f(0, size);
typedef TensorCostModel<ThreadPoolDevice> CostModel;
if (n <= 1 || numThreads() == 1 ||
CostModel::numThreads(n, cost, numThreads()) == 1) {
f(0, n);
return;
}
Index block_size = 1;
Index block_count = size;
if (min_block_size != -1) {
// Calculate block size based on (1) estimated cost and (2) parallel
// efficiency. We want blocks to be not too small to mitigate
// parallelization overheads; not too large to mitigate tail effect and
// potential load imbalance and we also want number of blocks to be evenly
// dividable across threads.
min_block_size = numext::maxi<Index>(min_block_size, 1);
block_size = numext::mini(min_block_size, size);
// Upper bound on block size:
const Index max_block_size = numext::mini(min_block_size * 2, size);
block_size = numext::mini(
alignBlockSize(block_size, hard_align, soft_align), size);
block_count = divup(size, block_size);
// Calculate parallel efficiency as fraction of total CPU time used for
// computations:
double max_efficiency =
static_cast<double>(block_count) /
(divup<int>(block_count, numThreads()) * numThreads());
// Now try to increase block size up to max_block_size as long as it
// doesn't decrease parallel efficiency.
for (Index prev_block_count = block_count; prev_block_count > 1;) {
// This is the next block size that divides size into a smaller number
// of blocks than the current block_size.
Index coarser_block_size = divup(size, prev_block_count - 1);
coarser_block_size =
alignBlockSize(coarser_block_size, hard_align, soft_align);
if (coarser_block_size > max_block_size) {
break; // Reached max block size. Stop.
}
// Recalculate parallel efficiency.
const Index coarser_block_count = divup(size, coarser_block_size);
eigen_assert(coarser_block_count < prev_block_count);
prev_block_count = coarser_block_count;
const double coarser_efficiency =
static_cast<double>(coarser_block_count) /
(divup<int>(coarser_block_count, numThreads()) * numThreads());
if (coarser_efficiency + 0.01 >= max_efficiency) {
// Taking it.
block_size = coarser_block_size;
block_count = coarser_block_count;
if (max_efficiency < coarser_efficiency) {
max_efficiency = coarser_efficiency;
}
// Calculate block size based on (1) the iteration cost and (2) parallel
// efficiency. We want blocks to be not too small to mitigate
// parallelization overheads; not too large to mitigate tail
// effect and potential load imbalance and we also want number
// of blocks to be evenly dividable across threads.
double block_size_f = 1.0 / CostModel::taskSize(1, cost);
Index block_size = numext::mini(n, numext::maxi<Index>(1, block_size_f));
const Index max_block_size =
numext::mini(n, numext::maxi<Index>(1, 2 * block_size_f));
if (block_align) {
Index new_block_size = block_align(block_size);
eigen_assert(new_block_size >= block_size);
block_size = numext::mini(n, new_block_size);
}
Index block_count = divup(n, block_size);
// Calculate parallel efficiency as fraction of total CPU time used for
// computations:
double max_efficiency =
static_cast<double>(block_count) /
(divup<int>(block_count, numThreads()) * numThreads());
// Now try to increase block size up to max_block_size as long as it
// doesn't decrease parallel efficiency.
for (Index prev_block_count = block_count; prev_block_count > 1;) {
// This is the next block size that divides size into a smaller number
// of blocks than the current block_size.
Index coarser_block_size = divup(n, prev_block_count - 1);
if (block_align) {
Index new_block_size = block_align(coarser_block_size);
eigen_assert(new_block_size >= coarser_block_size);
coarser_block_size = numext::mini(n, new_block_size);
}
if (coarser_block_size > max_block_size) {
break; // Reached max block size. Stop.
}
// Recalculate parallel efficiency.
const Index coarser_block_count = divup(n, coarser_block_size);
eigen_assert(coarser_block_count < prev_block_count);
prev_block_count = coarser_block_count;
const double coarser_efficiency =
static_cast<double>(coarser_block_count) /
(divup<int>(coarser_block_count, numThreads()) * numThreads());
if (coarser_efficiency + 0.01 >= max_efficiency) {
// Taking it.
block_size = coarser_block_size;
block_count = coarser_block_count;
if (max_efficiency < coarser_efficiency) {
max_efficiency = coarser_efficiency;
}
}
}
@ -251,26 +253,20 @@ struct ThreadPoolDevice {
}
// Split into halves and submit to the pool.
Index mid = first + divup((last - first) / 2, block_size) * block_size;
pool_->Schedule([=, &handleRange]() { handleRange(mid, last); });
pool_->Schedule([=, &handleRange]() { handleRange(first, mid); });
enqueue_func([=, &handleRange]() { handleRange(mid, last); });
enqueue_func([=, &handleRange]() { handleRange(first, mid); });
};
handleRange(0, size);
handleRange(0, n);
barrier.Wait();
}
private:
static Index alignBlockSize(Index size, Index hard_align, Index soft_align) {
if (soft_align > hard_align && size >= 4 * soft_align) {
// Align to soft_align, if it won't increase size by more than 25%.
return (size + soft_align - 1) & ~(soft_align - 1);
}
if (hard_align > 0) {
return (size + hard_align - 1) & ~(hard_align - 1);
}
return size;
// Convinience wrapper for parallelFor that does not align blocks.
void parallelFor(Index n, const TensorOpCost& cost,
std::function<void(Index, Index)> f) const {
parallelFor(n, cost, nullptr, std::move(f));
}
private:
ThreadPoolInterface* pool_;
size_t num_threads_;
};

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@ -137,6 +137,13 @@ class TensorExecutor<Expression, ThreadPoolDevice, Vectorizable> {
{
const Index PacketSize = Vectorizable ? unpacket_traits<typename Evaluator::PacketReturnType>::size : 1;
const Index size = array_prod(evaluator.dimensions());
#if defined(EIGEN_USE_NONBLOCKING_THREAD_POOL) && defined(EIGEN_USE_COST_MODEL)
device.parallelFor(size, evaluator.costPerCoeff(Vectorizable),
EvalRange::alignBlockSize,
[&evaluator](Index first, Index last) {
EvalRange::run(&evaluator, first, last);
});
#else
size_t num_threads = device.numThreads();
#ifdef EIGEN_USE_COST_MODEL
if (num_threads > 1) {
@ -163,11 +170,12 @@ class TensorExecutor<Expression, ThreadPoolDevice, Vectorizable> {
}
barrier.Wait();
}
#endif // EIGEN_USE_NONBLOCKING_THREAD_POOL
}
evaluator.cleanup();
}
};
#endif
#endif // EIGEN_USE_THREADS
// GPU: the evaluation of the expression is offloaded to a GPU.

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@ -13,77 +13,6 @@
namespace Eigen {
namespace internal {
/** \internal
* \brief Template functor to compute the modulo between an array and a scalar.
*/
template <typename Scalar>
struct scalar_mod_op {
EIGEN_DEVICE_FUNC scalar_mod_op(const Scalar& divisor) : m_divisor(divisor) {}
EIGEN_DEVICE_FUNC inline Scalar operator() (const Scalar& a) const { return a % m_divisor; }
const Scalar m_divisor;
};
template <typename Scalar>
struct functor_traits<scalar_mod_op<Scalar> >
{ enum { Cost = NumTraits<Scalar>::template Div<false>::Cost, PacketAccess = false }; };
/** \internal
* \brief Template functor to compute the modulo between 2 arrays.
*/
template <typename Scalar>
struct scalar_mod2_op {
EIGEN_EMPTY_STRUCT_CTOR(scalar_mod2_op);
EIGEN_DEVICE_FUNC inline Scalar operator() (const Scalar& a, const Scalar& b) const { return a % b; }
};
template <typename Scalar>
struct functor_traits<scalar_mod2_op<Scalar> >
{ enum { Cost = NumTraits<Scalar>::template Div<false>::Cost, PacketAccess = false }; };
template <typename Scalar>
struct scalar_fmod_op {
EIGEN_EMPTY_STRUCT_CTOR(scalar_fmod_op);
EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE Scalar
operator()(const Scalar& a, const Scalar& b) const {
return numext::fmod(a, b);
}
};
template <typename Scalar>
struct functor_traits<scalar_fmod_op<Scalar> > {
enum { Cost = 13, // Reciprocal throughput of FPREM on Haswell.
PacketAccess = false };
};
/** \internal
* \brief Template functor to compute the sigmoid of a scalar
* \sa class CwiseUnaryOp, ArrayBase::sigmoid()
*/
template <typename T>
struct scalar_sigmoid_op {
EIGEN_EMPTY_STRUCT_CTOR(scalar_sigmoid_op)
EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE T operator()(const T& x) const {
const T one = T(1);
return one / (one + numext::exp(-x));
}
template <typename Packet> EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
Packet packetOp(const Packet& x) const {
const Packet one = pset1<Packet>(T(1));
return pdiv(one, padd(one, pexp(pnegate(x))));
}
};
template <typename T>
struct functor_traits<scalar_sigmoid_op<T> > {
enum {
Cost = NumTraits<T>::AddCost * 2 + NumTraits<T>::MulCost * 6,
PacketAccess = packet_traits<T>::HasAdd && packet_traits<T>::HasDiv &&
packet_traits<T>::HasNegate && packet_traits<T>::HasExp
};
};
// Standard reduction functors
template <typename T> struct SumReducer
{