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cutlass/cutlass/gemm/gemm_shared_tile.h
2018-05-16 11:44:56 -07:00

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/*! \file
\brief Defines iterators for efficiently loading and storing tiles to and from shared memory.
*/
#pragma once
#include <cutlass/gemm/gemm_operand.h>
namespace cutlass {
namespace gemm {
////////////////////////////////////////////////////////////////////////////////////////////////////
template <typename Scalar_, typename Tile_, typename Threads_, int kScalarsPerSts_>
struct GemmSharedStoreTileAbTraits {
/// The scalar.
typedef typename platform::remove_const<Scalar_>::type Scalar;
/// The pointer.
typedef Scalar_* Pointer;
/// The tile.
typedef typename ReshapeTile<Tile_, kScalarsPerSts_>::Tile Tile;
/// The threads.
typedef Threads_ Threads;
/// The strides to compute the base position of the thread.
typedef Shape<0, ShapeCount<Tile>::kWc, Tile::kC, kScalarsPerSts_> ThreadsStrides;
/// The skew.
static int const kSkew = 0;
/// The number of scalars per LDG/STG.
static int const kAccessSize = kScalarsPerSts_;
/// The memory space.
static MemorySpace::Kind const kMemorySpace = MemorySpace::kShared;
/// The number of iterations needed to load/store the tile.
typedef Shape<1,
Tile::kH / Threads::kH,
Tile::kW / Threads::kW,
Tile::kC / Threads::kC / kAccessSize>
Iterations;
/// The strides in each dimension between different loads/stores.
typedef Shape<0, Threads::kH * ShapeCount<Tile>::kWc, Threads::kW * kAccessSize> Delta;
/// The strides in each dimension between different loads/stores.
typedef Shape<0, Threads::kH * ShapeCount<Tile>::kWc, Threads::kW * kAccessSize>
ImmediateOffsetStrides;
struct ThreadOffset {
CUTLASS_HOST_DEVICE
Coord<4> operator()() const {
int offset = ComputeThreadOffsetFromStrides<Threads, ThreadsStrides>::get();
return make_Coord(0, 0, offset, 0);
}
};
};
////////////////////////////////////////////////////////////////////////////////////////////////////
template <typename Scalar_, typename Tile_, typename Threads_, int kScalarsPerSts_, int kSkew_>
struct GemmSharedStoreWithSkewTileAbTraits {
/// The scalar.
typedef typename platform::remove_const<Scalar_>::type Scalar;
/// The pointer.
typedef Scalar_* Pointer;
/// The tile without skews.
typedef typename ReshapeTile<Tile_, kScalarsPerSts_>::Tile TileWithoutSkew;
/// The tile.
typedef typename ReshapeTile<Shape<Tile_::kD, Tile_::kH, Tile_::kW + kSkew_>,
kScalarsPerSts_>::Tile Tile;
/// The threads.
typedef Threads_ Threads;
/// The skew.
static int const kSkew = kSkew_;
/// The number of scalars per STS.
static int const kAccessSize = kScalarsPerSts_;
/// The memory space.
static MemorySpace::Kind const kMemorySpace = MemorySpace::kShared;
/// The number of iterations needed to load/store the tile.
typedef Shape<1, TileWithoutSkew::kH / Threads::kW, TileWithoutSkew::kW / Threads::kH> Iterations;
/// The strides in each dimension between different loads/stores.
typedef Shape<0, ShapeCount<Tile>::kWc, Threads::kH * kAccessSize> Delta;
/// The strides in each dimension between different loads/stores.
typedef Shape<0, ShapeCount<Tile>::kWc, Threads::kH * kAccessSize> ImmediateOffsetStrides;
struct ThreadOffset {
CUTLASS_HOST_DEVICE
Coord<4> operator()() const {
int offset = ComputeThreadOffsetFromStrides<Threads, ThreadsStrides>::get();
return make_Coord(0, 0, offset, 0);
}
};
protected:
/// The strides to compute the base position of the thread.
typedef Shape<0, kScalarsPerSts_, ShapeCount<Tile>::kHwc / Threads::kW> ThreadsStrides;
};
////////////////////////////////////////////////////////////////////////////////////////////////////
template <typename Scalar_,
typename OutputTile_,
typename Warps_,
typename ThreadsPerWarp_,
typename InstructionShape_,
int kStages_,
int kScalarsPerLds_,
int kSkew_ = 0>
struct GemmSharedLoadTileATraits {
static GemmOperand::Kind const kOperand = GemmOperand::kA;
/// The scalar.
typedef typename platform::remove_const<Scalar_>::type Scalar;
/// The pointer.
typedef Scalar_* Pointer;
/// The tile without skew.
typedef Shape<kStages_,
OutputTile_::kD / InstructionShape_::kD,
GetExtent<kOperand, OutputTile_>::kExtent * InstructionShape_::kD>
TileWithoutSkew_;
/// The tile with skew.
typedef Shape<kStages_, TileWithoutSkew_::kH, TileWithoutSkew_::kW + kSkew_> TileWithSkew;
/// The tile without skew after reshaping.
typedef typename ReshapeTile<TileWithoutSkew_, kScalarsPerLds_>::Tile TileWithoutSkew;
/// The tile.
typedef typename ReshapeTile<TileWithSkew, kScalarsPerLds_>::Tile Tile;
/// The number of warps.
typedef Warps_ Warps;
/// The threads in a warp.
typedef ThreadsPerWarp_ ThreadsPerWarp;
/// The number of scalars per LDG/STG.
// static int const kScalarsPerLds = kScalarsPerLds_;
static int const kAccessSize = kScalarsPerLds_;
/// The skew.
static int const kSkew = kSkew_;
/// The memory space.
static MemorySpace::Kind const kMemorySpace = MemorySpace::kShared;
/// The number of warps.
static int const kWarps = GetExtent<kOperand, Warps>::kExtent;
/// The number of threads in one dimension of the warp.
static int const kThreadsPerWarp = GetExtent<kOperand, ThreadsPerWarp>::kExtent;
/// The number of iterations needed to load/store the tile.
typedef Shape<1, 1, TileWithoutSkew::kW / kWarps / kThreadsPerWarp /* / kScalarsPerLds*/>
Iterations;
/// The strides in each dimension between different loads/stores.
typedef Shape<TileWithSkew::kW, 0, kWarps * kThreadsPerWarp * kAccessSize, 0> Delta;
/// The strides in each dimension between different loads/stores.
typedef Shape<TileWithSkew::kW, 0, kWarps * kThreadsPerWarp * kAccessSize, 0>
ImmediateOffsetStrides;
/// Computes the thread offset in (H, W) based on thread ID
struct ThreadOffset {
CUTLASS_HOST_DEVICE
Coord<4> operator()() const {
// Extract the warp.
int const warp = threadIdx.x / kWarpSize % Warps::kW;
// Compute the row offset for each thread
int const lane = (threadIdx.x & 0x0e) / 2;
// The offset.
int const offset = (warp * ThreadsPerWarp::kW + lane) * kAccessSize;
return make_Coord(0, 0, offset, 0);
}
};
};
////////////////////////////////////////////////////////////////////////////////////////////////////
template <typename Scalar_,
typename OutputTile_,
typename Warps_,
typename ThreadsPerWarp_,
typename InstructionShape_,
int kStages_,
int kScalarsPerLds_,
int kSkew_ = 0>
struct GemmSharedLoadTileBTraits {
static GemmOperand::Kind const kOperand = GemmOperand::kB;
/// The scalar.
typedef typename platform::remove_const<Scalar_>::type Scalar;
/// The pointer.
typedef Scalar_* Pointer;
/// The tile without skew.
typedef Shape<kStages_,
OutputTile_::kD / InstructionShape_::kD,
GetExtent<kOperand, OutputTile_>::kExtent * InstructionShape_::kD>
TileWithoutSkew_;
/// The tile with skew.
typedef Shape<kStages_, TileWithoutSkew_::kH, TileWithoutSkew_::kW + kSkew_> TileWithSkew;
/// The tile without skew after reshaping.
typedef typename ReshapeTile<TileWithoutSkew_, kScalarsPerLds_>::Tile TileWithoutSkew;
/// The tile.
typedef typename ReshapeTile<TileWithSkew, kScalarsPerLds_>::Tile Tile;
/// The number of warps.
typedef Warps_ Warps;
/// The threads in a warp.
typedef ThreadsPerWarp_ ThreadsPerWarp;
/// The number of scalars per LDG/STG.
static int const kAccessSize = kScalarsPerLds_;
/// The skew.
static int const kSkew = kSkew_;
/// The memory space.
static MemorySpace::Kind const kMemorySpace = MemorySpace::kShared;
/// The number of warps.
static int const kWarps = GetExtent<kOperand, Warps>::kExtent;
/// The number of threads in one dimension of the warp.
static int const kThreadsPerWarp = GetExtent<kOperand, ThreadsPerWarp>::kExtent;
/// The number of iterations needed to load/store the tile.
typedef Shape<1, 1, TileWithoutSkew::kW / kWarps / kThreadsPerWarp /* / kAccessSize*/> Iterations;
/// The strides in each dimension between different loads/stores.
typedef Shape<TileWithSkew::kW, 0, kWarps * kThreadsPerWarp * kAccessSize, 0> Delta;
/// The strides in each dimension between different loads/stores.
typedef Shape<TileWithSkew::kW, 0, kWarps * kThreadsPerWarp * kAccessSize, 0>
ImmediateOffsetStrides;
/// Computes the thread offset in (H, W) based on thread ID
struct ThreadOffset {
CUTLASS_HOST_DEVICE
Coord<4> operator()() const {
// The position of the warp.
int const warp = threadIdx.x / (Warps::kW * kWarpSize);
// Compute the column offset for each thread
int const lane = (threadIdx.x & 0x10) / 8 + (threadIdx.x & 0x01);
// The offset.
int const offset = (warp * ThreadsPerWarp::kH + lane) * kAccessSize;
return make_Coord(0, 0, offset, 0);
}
};
};
////////////////////////////////////////////////////////////////////////////////////////////////////
template <typename Scalar_,
typename OutputTile_,
typename Warps_,
typename ThreadsPerWarp_,
int kScalarsPerSts_,
int kSkew_ = 0>
struct GemmSharedStoreTileDTraits {
/// The scalar.
typedef typename platform::remove_const<Scalar_>::type Scalar;
/// The pointer.
typedef Scalar_* Pointer;
/// The dimension of the output tile.
typedef OutputTile_ OutputTile;
/// The warps in the tile.
typedef Warps_ Warps;
/// The threads in the warps.
typedef ThreadsPerWarp_ ThreadsPerWarp;
/// The number of scalars per LDG/STG.
static int const kAccessSize = kScalarsPerSts_;
/// The skew.
static int const kSkew = kSkew_;
/// The memory space.
static MemorySpace::Kind const kMemorySpace = MemorySpace::kShared;
/// The number of scalars per thread.
static int const kScalarsPerThread = OutputTile_::kW / Warps::kW / ThreadsPerWarp::kW;
/// The number of threads.
static int const kThreads = ShapeCount<Warps>::kCount * kWarpSize;
/// The number of scalars per row. We build a tile with 2 rows (to avoid bank conflicts).
static int const kScalarsPerRow = kThreads / 2 * kScalarsPerThread + kSkew;
/// The tile.
typedef Shape<1, 2, kScalarsPerRow / kAccessSize, kAccessSize> Tile;
/// The number of iterations needed to store the tile.
typedef Shape<1, 1, kScalarsPerThread / kAccessSize> Iterations;
/// The strides in each dimension between different loads/stores.
typedef Shape<0, 0, Warps::kW * ThreadsPerWarp::kW * kAccessSize> Delta;
/// The strides in each dimension between different loads/stores.
typedef Shape<0, 0, Warps::kW * ThreadsPerWarp::kW * kAccessSize> ImmediateOffsetStrides;
/// Computes the thread offset in (H, W) based on thread ID
struct ThreadOffset {
CUTLASS_HOST_DEVICE
Coord<4> operator()() const {
// We issue STS.128 in the epilogue to store the accumulators to shared memory. When we use
// STS.128, we have to guarantee that threads in groups of 8 do not have bank conflicts (i.e
// they write to different banks).
// Odd threads go to the second half of shared memory.
int const row = threadIdx.x & 0x01;
int const warp_id = (threadIdx.x >> 5);
int const warp_row = (warp_id % Warps::kW);
int const warp_col = (warp_id / Warps::kW);
int hi_halfwarp_offset = OutputTile::kW * ((threadIdx.x >> 4) & 1);
int lo_halfwarp_offset = (((threadIdx.x >> 1) & 0x7) + warp_row * ThreadsPerWarp::kW);
int col = kAccessSize * lo_halfwarp_offset +
warp_col * (ThreadsPerWarp::kH / 2) * OutputTile::kW + hi_halfwarp_offset;
int offset = row * kScalarsPerRow + col;
return make_Coord(0, 0, offset, 0);
}
};
};
////////////////////////////////////////////////////////////////////////////////////////////////////
template <typename Scalar_,
typename OutputTile_,
typename Warps_,
typename ThreadsPerWarp_,
int kTileH_,
int kScalarsPerLds_,
int kSkew_ = 0>
struct GemmSharedLoadTileDTraits {
/// The scalar.
typedef typename platform::remove_const<Scalar_>::type Scalar;
/// The pointer.
typedef Scalar_* Pointer;
/// The dimension of the output tile.
typedef OutputTile_ OutputTile;
/// The warps in the tile.
typedef Warps_ Warps;
/// The threads in the warps.
typedef ThreadsPerWarp_ ThreadsPerWarp;
/// The number of scalars per LDG/STG.
static int const kAccessSize = kScalarsPerLds_;
/// The skew.
static int const kSkew = kSkew_;
/// The memory space.
static MemorySpace::Kind const kMemorySpace = MemorySpace::kShared;
/// The number of scalars per thread.
static int const kScalarsPerThread = OutputTile_::kW / Warps::kW / ThreadsPerWarp::kW;
/// The number of threads.
static int const kThreads = ShapeCount<Warps>::kCount * kWarpSize;
/// The number of scalars per row. We build a tile with 2 rows (to avoid bank conflicts).
static int const kScalarsPerRow = kThreads / 2 * kScalarsPerThread + kSkew;
/// The tile.
typedef Shape<1, 2, kScalarsPerRow / kAccessSize, kAccessSize> Tile;
// Compute the number of iterations per warp in the Tile::kH dimension.
static int const kIterationsInHPerWarp = kTileH_ / ShapeCount<Warps>::kCount;
// As shown above, the shared memory tile is composed of 2 rows and each rows is made of
// kScalarsPerRow. A warp is expected to read from the 1st row, then move to the 2nd row and go
// back to the 1st row. To model that scheme we define the Iterations shape as Shape<X, 2, ...>.
// However, in some cases, we have only 1 iteration per warp. In that case, we must define the
// shape as Shape<1, 1, ...>. The following code does that.
static int const kIterationsH = kIterationsInHPerWarp == 1 ? 1 : 2;
// As soon as we know kIterationsH, it is trivial to compute kIterationsD:
static int const kIterationsD = kIterationsInHPerWarp / kIterationsH;
/// The number of iterations needed to store the tile.
typedef Shape<kIterationsD, kIterationsH, OutputTile::kW / kWarpSize / kAccessSize> Iterations;
/// The strides in each dimension between different loads/stores.
typedef Shape<OutputTile::kW, kScalarsPerRow, kWarpSize * kAccessSize> Delta;
/// The strides in each dimension between different loads/stores.
typedef Shape<OutputTile::kW, kScalarsPerRow, kWarpSize * kAccessSize> ImmediateOffsetStrides;
/// Computes the thread offset in (H, W) based on thread ID
struct ThreadOffset {
CUTLASS_HOST_DEVICE
Coord<4> operator()() const {
// Each warp works on a different column.
int const h = threadIdx.x / kWarpSize;
// Compute the row.
int const w = (threadIdx.x & (kWarpSize - 1)) * kAccessSize;
int offset = 0;
if (Iterations::kH == 1) {
int const row = h & 0x1;
int const col = h / 2;
offset = row * ShapeCount<Tile>::kWc + col * OutputTile::kW * Iterations::kD + w;
} else {
offset = h * OutputTile::kW * Iterations::kD + w;
}
return make_Coord(0, 0, offset, 0);
}
};
};
////////////////////////////////////////////////////////////////////////////////////////////////////
} // namespace gemm
} // namespace cutlass