cutlass/include/cutlass/gemm/kernel/gemm_universal.h
2020-09-25 10:34:46 -07:00

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/*! \file
\brief
*/
#pragma once
#include "cutlass/cutlass.h"
#include "cutlass/fast_math.h"
#include "cutlass/gemm/gemm.h"
#include "cutlass/matrix_coord.h"
#include "cutlass/complex.h"
#include "cutlass/semaphore.h"
#include "cutlass/trace.h"
/////////////////////////////////////////////////////////////////////////////////////////////////
namespace cutlass {
namespace gemm {
namespace kernel {
/////////////////////////////////////////////////////////////////////////////////////////////////
template <
typename Mma_, ///! Threadblock-scoped matrix multiply-accumulate
typename Epilogue_, ///! Epilogue
typename ThreadblockSwizzle_ ///! Threadblock swizzling function
>
struct GemmUniversal {
public:
using Mma = Mma_;
using Epilogue = Epilogue_;
using EpilogueOutputOp = typename Epilogue::OutputOp;
using ThreadblockSwizzle = ThreadblockSwizzle_;
using ElementA = typename Mma::IteratorA::Element;
using LayoutA = typename Mma::IteratorA::Layout;
using ElementB = typename Mma::IteratorB::Element;
using LayoutB = typename Mma::IteratorB::Layout;
using ElementC = typename Epilogue::OutputTileIterator::Element;
using LayoutC = typename Epilogue::OutputTileIterator::Layout;
static ComplexTransform const kTransformA = Mma::kTransformA;
static ComplexTransform const kTransformB = Mma::kTransformB;
using Operator = typename Mma::Operator;
using OperatorClass = typename Mma::Operator::OperatorClass;
using ThreadblockShape = typename Mma::Shape;
using WarpShape = typename Mma::Operator::Shape;
using InstructionShape = typename Mma::Policy::Operator::InstructionShape;
using ArchTag = typename Mma::ArchTag;
static int const kStages = Mma::kStages;
static int const kAlignmentA = Mma::IteratorA::AccessType::kElements;
static int const kAlignmentB = Mma::IteratorB::AccessType::kElements;
static int const kAlignmentC = Epilogue::OutputTileIterator::kElementsPerAccess;
/// Warp count (concept: GemmShape)
using WarpCount = typename Mma::WarpCount;
static int const kThreadCount = 32 * WarpCount::kCount;
/// Split-K preserves splits that are 128b aligned
static int const kSplitKAlignment = const_max(128 / sizeof_bits<ElementA>::value, 128 / sizeof_bits<ElementB>::value);
//
// Structures
//
/// Argument structure
struct Arguments {
//
// Data members
//
GemmUniversalMode mode;
GemmCoord problem_size;
int batch_count;
typename EpilogueOutputOp::Params epilogue;
void const * ptr_A;
void const * ptr_B;
void const * ptr_C;
void * ptr_D;
int64_t batch_stride_A;
int64_t batch_stride_B;
int64_t batch_stride_C;
int64_t batch_stride_D;
int lda;
int ldb;
int ldc;
int ldd;
//
// Methods
//
Arguments():
mode(GemmUniversalMode::kGemm),
batch_count(1),
ptr_A(nullptr), ptr_B(nullptr), ptr_C(nullptr), ptr_D(nullptr) { }
/// constructs an arguments structure
Arguments(
GemmUniversalMode mode,
GemmCoord problem_size,
int batch_count,
typename EpilogueOutputOp::Params epilogue,
void const * ptr_A,
void const * ptr_B,
void const * ptr_C,
void * ptr_D,
int64_t batch_stride_A,
int64_t batch_stride_B,
int64_t batch_stride_C,
int64_t batch_stride_D,
int lda,
int ldb,
int ldc,
int ldd
):
mode(mode),
problem_size(problem_size),
batch_count(batch_count),
epilogue(epilogue),
ptr_A(ptr_A), ptr_B(ptr_B), ptr_C(ptr_C), ptr_D(ptr_D),
batch_stride_A(batch_stride_A), batch_stride_B(batch_stride_B), batch_stride_C(batch_stride_C), batch_stride_D(batch_stride_D),
lda(lda), ldb(ldb), ldc(ldc), ldd(ldd) {
CUTLASS_TRACE_HOST("GemmUniversal::Arguments::Arguments() - problem_size: " << problem_size);
}
/// Returns arguments for the transposed problem
Arguments transposed_problem() const {
Arguments args(*this);
std::swap(args.problem_size.m(), args.problem_size.n());
std::swap(args.ptr_A, args.ptr_B);
std::swap(args.lda, args.ldb);
std::swap(args.batch_stride_A, args.batch_stride_B);
return args;
}
};
//
// Structure for precomputing values in host memory and passing to kernels
//
/// Parameters structure
struct Params {
cutlass::gemm::GemmCoord problem_size;
cutlass::gemm::GemmCoord grid_tiled_shape;
typename Mma::IteratorA::Params params_A;
typename Mma::IteratorB::Params params_B;
typename Epilogue::OutputTileIterator::Params params_C;
typename Epilogue::OutputTileIterator::Params params_D;
typename EpilogueOutputOp::Params output_op;
GemmUniversalMode mode;
int batch_count;
int gemm_k_size;
void * ptr_A;
void * ptr_B;
void * ptr_C;
void * ptr_D;
int64_t batch_stride_A;
int64_t batch_stride_B;
int64_t batch_stride_C;
int64_t batch_stride_D;
int *semaphore;
//
// Methods
//
CUTLASS_HOST_DEVICE
Params():
params_A(0),
params_B(0),
params_C(0),
params_D(0),
batch_count(0),
gemm_k_size(0),
mode(cutlass::gemm::GemmUniversalMode::kGemm),
ptr_A(nullptr),
ptr_B(nullptr),
ptr_C(nullptr),
ptr_D(nullptr),
batch_stride_A(0),
batch_stride_B(0),
batch_stride_C(0),
batch_stride_D(0),
semaphore(nullptr) { }
CUTLASS_HOST_DEVICE
Params(
Arguments const &args,
cutlass::gemm::GemmCoord const & grid_tiled_shape,
int gemm_k_size,
void *workspace = nullptr
):
problem_size(args.problem_size),
grid_tiled_shape(grid_tiled_shape),
params_A(args.lda),
params_B(args.ldb),
params_C(args.ldc),
params_D(args.ldd),
output_op(args.epilogue),
mode(args.mode),
batch_count(args.batch_count),
gemm_k_size(gemm_k_size),
ptr_A(const_cast<void *>(args.ptr_A)),
ptr_B(const_cast<void *>(args.ptr_B)),
ptr_C(const_cast<void *>(args.ptr_C)),
ptr_D(args.ptr_D),
batch_stride_A(args.batch_stride_A),
batch_stride_B(args.batch_stride_B),
batch_stride_C(args.batch_stride_C),
batch_stride_D(args.batch_stride_D),
semaphore(static_cast<int *>(workspace)) {
CUTLASS_TRACE_HOST("GemmUniversal::Params::Params() - problem_size: " << problem_size);
}
CUTLASS_HOST_DEVICE
void update(
Arguments const &args,
void *workspace = nullptr) {
ptr_A = const_cast<void *>(args.ptr_A);
ptr_B = const_cast<void *>(args.ptr_B);
ptr_C = const_cast<void *>(args.ptr_C);
ptr_D = args.ptr_D;
batch_stride_A = args.batch_stride_A;
batch_stride_B = args.batch_stride_B;
batch_stride_C = args.batch_stride_C;
batch_stride_D = args.batch_stride_D;
output_op = args.epilogue;
semaphore = static_cast<int *>(workspace);
CUTLASS_TRACE_HOST("GemmUniversal::Params::update()");
}
};
/// Shared memory storage structure
union SharedStorage {
typename Mma::SharedStorage main_loop;
typename Epilogue::SharedStorage epilogue;
};
public:
//
// Methods
//
CUTLASS_DEVICE
GemmUniversal() { }
/// Determines whether kernel satisfies alignment
static Status can_implement(
cutlass::gemm::GemmCoord const & problem_size) {
CUTLASS_TRACE_HOST("GemmUniversal::can_implement()");
static int const kAlignmentA = Mma::IteratorA::AccessType::kElements;
static int const kAlignmentB = Mma::IteratorB::AccessType::kElements;
static int const kAlignmentC = Epilogue::OutputTileIterator::kElementsPerAccess;
if ((problem_size.m() % kAlignmentA) || (problem_size.k() % kAlignmentA) ||
(problem_size.n() % kAlignmentB) || (problem_size.k() % kAlignmentB) ||
(problem_size.m() % kAlignmentC) || (problem_size.n() % kAlignmentC)) {
CUTLASS_TRACE_HOST(" returning kErrorMisalignedOperand");
return Status::kErrorMisalignedOperand;
}
CUTLASS_TRACE_HOST(" returning kSuccess");
return Status::kSuccess;
}
static Status can_implement(Arguments const &args) {
return can_implement(args.problem_size);
}
/// Executes one GEMM
CUTLASS_DEVICE
void operator()(Params const &params, SharedStorage &shared_storage) {
// Compute threadblock location
ThreadblockSwizzle threadblock_swizzle;
cutlass::gemm::GemmCoord threadblock_tile_offset =
threadblock_swizzle.get_tile_offset(params.grid_tiled_shape);
// Early exit if CTA is out of range
if (params.grid_tiled_shape.m() <= threadblock_tile_offset.m() ||
params.grid_tiled_shape.n() <= threadblock_tile_offset.n()) {
return;
}
int offset_k = 0;
int problem_size_k = params.problem_size.k();
ElementA *ptr_A = static_cast<ElementA *>(params.ptr_A);
ElementB *ptr_B = static_cast<ElementB *>(params.ptr_B);
//
// Fetch pointers based on mode.
//
if (params.mode == GemmUniversalMode::kGemm ||
params.mode == GemmUniversalMode::kGemmSplitKParallel) {
if (threadblock_tile_offset.k() + 1 < params.grid_tiled_shape.k()) {
problem_size_k = (threadblock_tile_offset.k() + 1) * params.gemm_k_size;
}
offset_k = threadblock_tile_offset.k() * params.gemm_k_size;
}
else if (params.mode == GemmUniversalMode::kBatched) {
ptr_A += threadblock_tile_offset.k() * params.batch_stride_A;
ptr_B += threadblock_tile_offset.k() * params.batch_stride_B;
}
else if (params.mode == GemmUniversalMode::kArray) {
ptr_A = static_cast<ElementA * const *>(params.ptr_A)[threadblock_tile_offset.k()];
ptr_B = static_cast<ElementB * const *>(params.ptr_B)[threadblock_tile_offset.k()];
}
__syncthreads();
// Compute initial location in logical coordinates
cutlass::MatrixCoord tb_offset_A{
threadblock_tile_offset.m() * Mma::Shape::kM,
offset_k,
};
cutlass::MatrixCoord tb_offset_B{
offset_k,
threadblock_tile_offset.n() * Mma::Shape::kN
};
// Compute position within threadblock
int thread_idx = threadIdx.x;
// Construct iterators to A and B operands
typename Mma::IteratorA iterator_A(
params.params_A,
ptr_A,
{params.problem_size.m(), problem_size_k},
thread_idx,
tb_offset_A);
typename Mma::IteratorB iterator_B(
params.params_B,
ptr_B,
{problem_size_k, params.problem_size.n()},
thread_idx,
tb_offset_B);
// Broadcast the warp_id computed by lane 0 to ensure dependent code
// is compiled as warp-uniform.
int warp_idx = __shfl_sync(0xffffffff, threadIdx.x / 32, 0);
int lane_idx = threadIdx.x % 32;
//
// Main loop
//
// Construct thread-scoped matrix multiply
Mma mma(shared_storage.main_loop, thread_idx, warp_idx, lane_idx);
typename Mma::FragmentC accumulators;
accumulators.clear();
// Compute threadblock-scoped matrix multiply-add
int gemm_k_iterations = (problem_size_k - offset_k + Mma::Shape::kK - 1) / Mma::Shape::kK;
// Compute threadblock-scoped matrix multiply-add
mma(
gemm_k_iterations,
accumulators,
iterator_A,
iterator_B,
accumulators);
//
// Epilogue
//
EpilogueOutputOp output_op(params.output_op);
//
// Masked tile iterators constructed from members
//
threadblock_tile_offset =
threadblock_swizzle.get_tile_offset(params.grid_tiled_shape);
//assume identity swizzle
MatrixCoord threadblock_offset(
threadblock_tile_offset.m() * Mma::Shape::kM,
threadblock_tile_offset.n() * Mma::Shape::kN
);
int block_idx = threadblock_tile_offset.m() + threadblock_tile_offset.n() * params.grid_tiled_shape.m();
ElementC *ptr_C = static_cast<ElementC *>(params.ptr_C);
ElementC *ptr_D = static_cast<ElementC *>(params.ptr_D);
//
// Fetch pointers based on mode.
//
// Construct the semaphore.
Semaphore semaphore(params.semaphore + block_idx, thread_idx);
if (params.mode == GemmUniversalMode::kGemm) {
// If performing a reduction via split-K, fetch the initial synchronization
if (params.grid_tiled_shape.k() > 1) {
// Fetch the synchronization lock initially but do not block.
semaphore.fetch();
// Indicate which position in a serial reduction the output operator is currently updating
output_op.set_k_partition(threadblock_tile_offset.k());
}
}
else if (params.mode == GemmUniversalMode::kGemmSplitKParallel) {
ptr_D += threadblock_tile_offset.k() * params.batch_stride_D;
}
else if (params.mode == GemmUniversalMode::kBatched) {
ptr_C += threadblock_tile_offset.k() * params.batch_stride_C;
ptr_D += threadblock_tile_offset.k() * params.batch_stride_D;
}
else if (params.mode == GemmUniversalMode::kArray) {
ptr_C = static_cast<ElementC * const *>(params.ptr_C)[threadblock_tile_offset.k()];
ptr_D = static_cast<ElementC * const *>(params.ptr_D)[threadblock_tile_offset.k()];
}
// Tile iterator loading from source tensor.
typename Epilogue::OutputTileIterator iterator_C(
params.params_C,
ptr_C,
params.problem_size.mn(),
thread_idx,
threadblock_offset
);
// Tile iterator writing to destination tensor.
typename Epilogue::OutputTileIterator iterator_D(
params.params_D,
ptr_D,
params.problem_size.mn(),
thread_idx,
threadblock_offset
);
Epilogue epilogue(
shared_storage.epilogue,
thread_idx,
warp_idx,
lane_idx);
// Wait on the semaphore - this latency may have been covered by iterator construction
if (params.mode == GemmUniversalMode::kGemm && params.grid_tiled_shape.k() > 1) {
// For subsequent threadblocks, the source matrix is held in the 'D' tensor.
if (threadblock_tile_offset.k()) {
iterator_C = iterator_D;
}
semaphore.wait(threadblock_tile_offset.k());
__threadfence();
}
// Execute the epilogue operator to update the destination tensor.
epilogue(
output_op,
iterator_D,
accumulators,
iterator_C);
//
// Release the semaphore
//
if (params.mode == GemmUniversalMode::kGemm && params.grid_tiled_shape.k() > 1) {
int lock = 0;
if (params.grid_tiled_shape.k() == threadblock_tile_offset.k() + 1) {
// The final threadblock resets the semaphore for subsequent grids.
lock = 0;
}
else {
// Otherwise, the semaphore is incremented
lock = threadblock_tile_offset.k() + 1;
}
semaphore.release(lock);
}
}
};
/////////////////////////////////////////////////////////////////////////////////////////////////
} // namespace kernel
} // namespace gemm
} // namespace cutlass
/////////////////////////////////////////////////////////////////////////////////////////////////