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cutlass/include/cutlass/epilogue/threadblock/output_tile_thread_map.h
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Andrew Kerr fb335f6a5f CUTLASS 2.0 (#62)
CUTLASS 2.0

Substantially refactored for

- Better performance, particularly for native Turing Tensor Cores
- Robust and durable templates spanning the design space
- Encapsulated functionality embodying modern C++11 programming techniques
- Optimized containers and data types for efficient, generic, portable device code

Updates to:
- Quick start guide
- Documentation
- Utilities
- CUTLASS Profiler

Native Turing Tensor Cores
- Efficient GEMM kernels targeting Turing Tensor Cores
- Mixed-precision floating point, 8-bit integer, 4-bit integer, and binarized operands

Coverage of existing CUTLASS functionality:
- GEMM kernels targeting CUDA and Tensor Cores in NVIDIA GPUs
- Volta Tensor Cores through native mma.sync and through WMMA API
- Optimizations such as parallel reductions, threadblock rasterization, and intra-threadblock reductions
- Batched GEMM operations
- Complex-valued GEMMs

Note: this commit and all that follow require a host compiler supporting C++11 or greater.
2019-11-19 16:55:34 -08:00

497 lines
16 KiB
C++

/***************************************************************************************************
* Copyright (c) 2017-2019, NVIDIA CORPORATION. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification, are permitted
* provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright notice, this list of
* conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright notice, this list of
* conditions and the following disclaimer in the documentation and/or other materials
* provided with the distribution.
* * Neither the name of the NVIDIA CORPORATION nor the names of its contributors may be used
* to endorse or promote products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
* FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL NVIDIA CORPORATION BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TOR (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
**************************************************************************************************/
/*! \file
\brief Metaprogram for determining the mapping of output elements to threads for epilogue tiles.
*/
#pragma once
#include "cutlass/cutlass.h"
#include "cutlass/numeric_types.h"
#include "cutlass/array.h"
#include "cutlass/layout/matrix.h"
#include "cutlass/matrix_shape.h"
#include "cutlass/tensor_ref.h"
#include "cutlass/fast_math.h"
////////////////////////////////////////////////////////////////////////////////
namespace cutlass {
namespace epilogue {
namespace threadblock {
////////////////////////////////////////////////////////////////////////////////
/// Tuple defining point in output tile
template <
int Column,
int Row,
int Group,
int Cluster,
int Tile
>
struct OutputTileShape {
static int const kColumn = Column;
static int const kRow = Row;
static int const kGroup = Group;
static int const kCluster = Cluster;
static int const kTile = Tile;
static int const kCount = kColumn * kRow * kGroup * kCluster * kTile;
};
////////////////////////////////////////////////////////////////////////////////
template <
typename ThreadMap_,
typename Shape_,
typename Iterations_,
typename Delta_,
typename Count_
>
struct OutputTileThreadMap {
/// Conventional thread map (concept: ThreadMap)
using ThreadMap = ThreadMap_;
/// Number of threads participating in the operation
static int const kThreads = ThreadMap::kThreads;
/// Number of scalar elements per access
static int const kElementsPerAccess = ThreadMap::kElementsPerAccess;
/// Shape of the tile
using Shape = Shape_;
/// Iterations performed by each thread
using Iterations = Iterations_;
/// Delta between accesses
using Delta = Delta_;
/// Number of iterator iterations
using Count = Count_;
/// Initial offset function
CUTLASS_HOST_DEVICE
static MatrixCoord initial_offset(int thread_idx) {
using Index = typename layout::PitchLinearCoord::Index;
layout::PitchLinearCoord coord = ThreadMap::initial_offset(thread_idx);
Index cluster = coord.strided() / (Shape::kGroup * Shape::kRow);
Index cluster_residual = coord.strided() % (Shape::kGroup * Shape::kRow);
Index group = cluster_residual / (Shape::kRow);
Index row = cluster_residual % (Shape::kRow);
return MatrixCoord{
row + group * Shape::kRow * Count::kRow
+ cluster * Shape::kGroup * Count::kGroup * Shape::kRow * Count::kRow,
coord.contiguous()
};
}
};
////////////////////////////////////////////////////////////////////////////////
namespace detail {
/// RowArrangement determines how one or more warps cover a region of consecutive rows.
template <
typename Shape,
int WarpsRemaining,
int ElementsPerAccess,
int ElementSize,
bool Is2dTile
>
struct RowArrangement;
/// RowArrangement in which each warp's access is a 1D tiled arrangement.
template <
typename Shape,
int WarpsRemaining,
int ElementsPerAccess,
int ElementSize
>
struct RowArrangement<Shape, WarpsRemaining, ElementsPerAccess, ElementSize, false> {
static int const kWarpSize = 32;
static int const kElementsPerAccess = ElementsPerAccess;
static int const kElementSize = ElementSize;
static int const kIterationsRow = 1;
static int const kDeltaRow = 1;
static int const kIterationsColumn = Shape::kColumn / kElementsPerAccess / kWarpSize;
static int const kDeltaColumn = kWarpSize * kElementsPerAccess;
static int const kAccessWidth = kWarpSize;
static int const kAccessRows = 1;
static int const kWarpPartitionsRow = 1;
static int const kWarpPartitionsColumn = WarpsRemaining;
};
/// RowArrangement in which each warp's access is a 2D tiled arrangement.
template <
typename Shape,
int WarpsRemaining,
int ElementsPerAccess,
int ElementSize
>
struct RowArrangement<Shape, WarpsRemaining, ElementsPerAccess, ElementSize, true> {
static int const kMemoryAccessSize = 128;
static int const kWarpSize = 32;
static int const kElementsPerAccess = ElementsPerAccess;
static int const kElementSize = ElementSize;
struct Detail {
static int const kShapeRow = Shape::kRow / WarpsRemaining;
static int const kShapeWidth = Shape::kColumn / kElementsPerAccess;
static int const kTargetMemoryAccessWidth =
kMemoryAccessSize / (kElementsPerAccess * kElementSize / 8);
static int const kTargetAccessRows = kWarpSize / kTargetMemoryAccessWidth;
};
static int const kAccessWidth =
(Detail::kTargetAccessRows > Detail::kShapeRow ?
kWarpSize / Detail::kShapeRow
: const_min(
Detail::kShapeWidth,
const_min(kWarpSize, kMemoryAccessSize / (kElementsPerAccess * kElementSize / 8))
));
static int const kAccessRows =
(Detail::kTargetAccessRows > Detail::kShapeRow ?
Detail::kShapeRow
: const_min(Shape::kRow, kWarpSize / kAccessWidth));
static int const kIterationsRow = Detail::kShapeRow / kAccessRows;
static int const kDeltaRow = kAccessRows;
static int const kIterationsColumn = Detail::kShapeWidth / kAccessWidth;
static int const kDeltaColumn = kAccessWidth * kElementsPerAccess;
static_assert( kAccessWidth * kElementsPerAccess <= Shape::kColumn, "Accessing too many elements per access");
static_assert( kIterationsColumn > 0, "Iteration Count Column must be > 0" );
static_assert( kIterationsRow > 0, "Iteration Count Row must be > 0" );
static int const kWarpPartitionsRow = 1;
static int const kWarpPartitionsColumn = 1;
};
}
////////////////////////////////////////////////////////////////////////////////
/// Template metaprogram for partitioning a 4D space across warps to achieve several performance
/// objectives:
///
/// - coalesced memory accesses in units of 128 Byte lines
/// - minimal address arithmetic
/// - minimal predicate calculations
///
template <
typename Shape_,
typename Count_,
int Threads,
int ElementsPerAccess,
int ElementSize
>
struct OutputTileOptimalThreadMap {
using Shape = Shape_;
using Count = Count_;
static int const kWarpSize = 32;
static int const kThreads = Threads;
static int const kWarpCount = kThreads / kWarpSize;
static int const kElementsPerAccess = ElementsPerAccess;
static int const kElementSize = ElementSize;
//
// Metaprogram computation
//
struct Detail {
// Clusters
static int const kIterationsCluster =
((Shape::kCluster > kWarpCount) ?
Shape::kCluster / kWarpCount
: 1);
static int const kDeltaCluster =
((Shape::kCluster > kWarpCount) ?
Shape::kRow * Count::kRow * Shape::kGroup * Count::kGroup * Shape::kCluster / kIterationsCluster
: 1);
static int const kCompactedDeltaCluster =
((Shape::kCluster > kWarpCount) ?
Shape::kRow * Shape::kGroup * Shape::kCluster / kIterationsCluster
: 1);
static int const kWarpPartitionsCluster =
((Shape::kCluster > kWarpCount) ?
kWarpCount
: kWarpCount / Shape::kCluster);
static int const kWarpsRemainingForGroups =
((Shape::kCluster > kWarpCount) ? 1 : kWarpCount / Shape::kCluster);
// Groups
static int const kIterationsGroup =
((Shape::kGroup > kWarpsRemainingForGroups) ?
Shape::kGroup / kWarpsRemainingForGroups
: 1);
static int const kDeltaGroup =
((Shape::kGroup > kWarpsRemainingForGroups) ?
Shape::kRow * Count::kRow * Shape::kGroup / kIterationsGroup
: 1);
static int const kCompactedDeltaGroup =
((Shape::kGroup > kWarpsRemainingForGroups) ?
Shape::kRow * Shape::kGroup / kIterationsGroup
: 1);
static int const kWarpPartitionsGroup =
((Shape::kGroup > kWarpsRemainingForGroups) ?
1
: kWarpsRemainingForGroups / Shape::kGroup);
static int const kWarpsRemainingForRows =
((Shape::kGroup > kWarpsRemainingForGroups) ?
1
: kWarpsRemainingForGroups / Shape::kGroup);
// Rows
using RowArrangement = detail::RowArrangement<
Shape,
kWarpsRemainingForRows,
kElementsPerAccess,
kElementSize,
(Shape::kRow > kWarpsRemainingForRows)
>;
// Warp partitions
using WarpPartitions = OutputTileShape<
RowArrangement::kWarpPartitionsColumn,
RowArrangement::kWarpPartitionsRow,
kWarpPartitionsGroup,
kWarpPartitionsCluster,
1>;
static int const kAccessWidth = RowArrangement::kAccessWidth;
static int const kAccessRows = RowArrangement::kAccessRows;
};
//
// Output
//
using Iterations = OutputTileShape<
Detail::RowArrangement::kIterationsColumn,
Detail::RowArrangement::kIterationsRow,
Detail::kIterationsGroup,
Detail::kIterationsCluster,
1>;
using Delta = OutputTileShape<
Detail::RowArrangement::kDeltaColumn,
Detail::RowArrangement::kDeltaRow,
Detail::kDeltaGroup,
Detail::kDeltaCluster,
1>;
/// Initial offset function
CUTLASS_HOST_DEVICE
static MatrixCoord initial_offset(int thread_idx) {
int warp_idx = thread_idx / kWarpSize;
int lane_idx = thread_idx % kWarpSize;
// Compute warp location
int cluster_idx = warp_idx / Detail::WarpPartitions::kCluster;
int residual_cluster = warp_idx % Detail::WarpPartitions::kCluster;
int group_idx = residual_cluster / Detail::WarpPartitions::kGroup;
int residual_group = residual_cluster % Detail::WarpPartitions::kGroup;
int row_idx = residual_group / Detail::WarpPartitions::kRow;
int col_idx = residual_group % Detail::WarpPartitions::kRow;
// Compute per-lane offset
int lane_row_offset = lane_idx / Detail::kAccessWidth;
int lane_col_offset = lane_idx % Detail::kAccessWidth;
// Compute coordinate in output space
int cluster_offset = cluster_idx * Shape::kRow * Count::kRow * Shape::kGroup * Count::kGroup;
int group_offset = group_idx * Shape::kRow * Count::kRow;
int row_offset = row_idx * Iterations::kRow * Detail::kAccessRows;
int column_offset = col_idx * Iterations::kColumn * Detail::kAccessWidth * kElementsPerAccess;
return MatrixCoord(
cluster_offset + group_offset + row_offset + lane_row_offset,
(column_offset + lane_col_offset) * kElementsPerAccess
);
}
/// Compacted thread map in which the 4D region is contiguous
struct CompactedThreadMap {
using Shape = Shape_;
using Iterations = OutputTileShape<
Detail::RowArrangement::kIterationsColumn,
Detail::RowArrangement::kIterationsRow,
Detail::kIterationsGroup,
Detail::kIterationsCluster,
1>;
using Delta = OutputTileShape<
Detail::RowArrangement::kDeltaColumn,
Detail::RowArrangement::kDeltaRow,
Detail::kCompactedDeltaGroup,
Detail::kCompactedDeltaCluster,
1>;
/// Number of elements within each vector access
static int const kElementsPerAccess = ElementsPerAccess;
/// Number of threads
static int const kThreads = Threads;
/// Function to compute each thread's initial offset
CUTLASS_HOST_DEVICE
static MatrixCoord initial_offset(int thread_idx) {
int warp_idx = thread_idx / kWarpSize;
int lane_idx = thread_idx % kWarpSize;
// Compute warp location
int cluster_idx = warp_idx / Detail::WarpPartitions::kCluster;
int residual_cluster = warp_idx % Detail::WarpPartitions::kCluster;
int group_idx = residual_cluster / Detail::WarpPartitions::kGroup;
int residual_group = residual_cluster % Detail::WarpPartitions::kGroup;
int row_idx = residual_group / Detail::WarpPartitions::kRow;
int col_idx = residual_group % Detail::WarpPartitions::kRow;
// Compute per-lane offset
int lane_row_offset = lane_idx / Detail::kAccessWidth;
int lane_col_offset = lane_idx % Detail::kAccessWidth;
// Compute coordinate in output space
int cluster_offset = cluster_idx * Shape::kRow * Shape::kGroup;
int group_offset = group_idx * Shape::kRow;
int row_offset = row_idx * Iterations::kRow * Detail::kAccessRows;
int column_offset = col_idx * Iterations::kColumn * Detail::kAccessWidth * kElementsPerAccess;
MatrixCoord coord(
cluster_offset + group_offset + row_offset + lane_row_offset,
(column_offset + lane_col_offset) * kElementsPerAccess
);
return coord;
}
};
};
////////////////////////////////////////////////////////////////////////////////
/// Template metaprogram for partitioning a 3D interleaved layout across warps
/// to achieve several performance objectives:
///
/// - coalesced memory accesses in units of 64 Byte lines
/// - minimal address arithmetic
/// - minimal predicate calculations
///
template <typename WarpCount_, typename MmaCount_, int Threads,
int ElementsPerAccess, int ElementSize>
struct InterleavedOutputTileThreadMap {
using WarpCount = WarpCount_;
using MmaCount = MmaCount_;
static int const kWarpSize = 32;
static int const kThreads = Threads;
static int const kWarpCount = kThreads / kWarpSize;
static int const kElementsPerAccess = ElementsPerAccess;
static int const kElementSize = ElementSize;
//
// Metaprogram computation
//
struct Detail {};
//
// Output
//
using Iterations = MmaCount;
using Delta = layout::PitchLinearShape<kWarpSize * kElementsPerAccess, 1>;
/// Initial offset function
CUTLASS_HOST_DEVICE
static layout::PitchLinearCoord initial_offset(int thread_idx) {
int warp_idx = thread_idx / kWarpSize;
int lane_idx = thread_idx % kWarpSize;
// Compute warp location
layout::PitchLinearCoord warp_footprint{
Delta::kContiguous * Iterations::kContiguous,
Delta::kStrided * Iterations::kStrided};
layout::PitchLinearCoord warp_offset{warp_idx % WarpCount::kContiguous,
warp_idx / WarpCount::kContiguous};
// Compute per-lane offset
layout::PitchLinearCoord thread_offset_in_warp{
lane_idx * kElementsPerAccess, 0};
layout::PitchLinearCoord thread_offset_in_threadblock_tile =
warp_footprint * warp_offset + thread_offset_in_warp;
return thread_offset_in_threadblock_tile;
}
};
////////////////////////////////////////////////////////////////////////////////
} // namespace threadblock
} // namespace epilogue
} // namespace cutlass