cutlass/include/cute/algorithm/gemm.hpp
ANIKET SHIVAM 90d3b0fb18
CUTLASS 3.2.1 (#1113)
* Updates for 3.2.1 release.

* Minor fix in gemm op profiler for raster order.

* Add scheduler mapping for raster order in the kernels.
2023-09-26 17:24:26 -04:00

741 lines
26 KiB
C++

/***************************************************************************************************
* Copyright (c) 2023 - 2023 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
* SPDX-License-Identifier: BSD-3-Clause
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#pragma once
#include <cute/config.hpp>
#include <cute/util/type_traits.hpp>
#include <cute/algorithm/functional.hpp>
#include <cute/tensor.hpp>
#include <cute/atom/mma_atom.hpp>
/** The gemm algorithm takes four (or three) tensors and computes
* D = A * B + C
* It dispatches based on the number of modes each tensor has:
*
* 1. `(V) x (V) => (V)`.
* The element-wise product of vectors. Dispatches to FMA or MMA.
* 2. `(M) x (N) => (M,N)`.
* The outer product of vectors. Dispatches to [3] with new mode K=(1).
* 3. `(M,K) x (N,K) => (M,N)`.
* The product of matrices. Dispatches to [5] with MMA vector-mode V.
* 4. `(V,M) x (V,N) => (V,M,N)`.
* The batched outer product of vectors. Accounts for register reuse and dispatches to [1] for each (m,n).
* 5. `(V,M,K) x (V,N,K) => (V,M,N)`.
* The batched product of matrices. Dispatches to [4] for each (k).
*/
namespace cute
{
//
// Three arguments to four
//
template <class TA, class ALayout,
class TB, class BLayout,
class TC, class CLayout>
CUTE_HOST_DEVICE
void
gemm(Tensor<TA, ALayout> const& A,
Tensor<TB, BLayout> const& B,
Tensor<TC, CLayout> & C)
{
return gemm(C, A, B, C);
}
template <class MMA,
class TA, class ALayout,
class TB, class BLayout,
class TC, class CLayout>
CUTE_HOST_DEVICE
void
gemm(MMA_Atom<MMA> const& mma,
Tensor<TA, ALayout> const& A,
Tensor<TB, BLayout> const& B,
Tensor<TC, CLayout> & C)
{
return gemm(mma, C, A, B, C);
}
//
// Accept mutable temporaries
//
template <class TA, class ALayout,
class TB, class BLayout,
class TC, class CLayout>
CUTE_HOST_DEVICE
void
gemm(Tensor<TA, ALayout> const& A,
Tensor<TB, BLayout> const& B,
Tensor<TC, CLayout> && C)
{
return gemm(C, A, B, C);
}
template <class TD, class DLayout,
class TA, class ALayout,
class TB, class BLayout,
class TC, class CLayout>
CUTE_HOST_DEVICE
void
gemm(Tensor<TD, DLayout> && D,
Tensor<TA, ALayout> const& A,
Tensor<TB, BLayout> const& B,
Tensor<TC, CLayout> const& C)
{
return gemm(D, A, B, C);
}
template <class MMA,
class TA, class ALayout,
class TB, class BLayout,
class TC, class CLayout>
CUTE_HOST_DEVICE
void
gemm(MMA_Atom<MMA> const& mma,
Tensor<TA, ALayout> const& A,
Tensor<TB, BLayout> const& B,
Tensor<TC, CLayout> && C)
{
return gemm(mma, C, A, B, C);
}
template <class MMA,
class TD, class DLayout,
class TA, class ALayout,
class TB, class BLayout,
class TC, class CLayout>
CUTE_HOST_DEVICE
void
gemm(MMA_Atom<MMA> const& mma,
Tensor<TD, DLayout> && D,
Tensor<TA, ALayout> const& A,
Tensor<TB, BLayout> const& B,
Tensor<TC, CLayout> const& C)
{
return gemm(mma, D, A, B, C);
}
//
// Default MMA is UniversalFMA
//
template <class TD, class DLayout,
class TA, class ALayout,
class TB, class BLayout,
class TC, class CLayout>
CUTE_HOST_DEVICE
void
gemm(Tensor<TD, DLayout> & D,
Tensor<TA, ALayout> const& A,
Tensor<TB, BLayout> const& B,
Tensor<TC, CLayout> const& C)
{
using MMA = MMA_Atom<UniversalFMA<typename Tensor<TD,DLayout>::value_type,
typename Tensor<TA,ALayout>::value_type,
typename Tensor<TB,BLayout>::value_type,
typename Tensor<TC,CLayout>::value_type>>;
return gemm(MMA{}, D, A, B, C);
}
//
// Thread-Local Register-Memory GEMMs
//
// Dispatch [1]: (V) x (V) => (V)
template <class MMA,
class TD, class DLayout,
class TA, class ALayout,
class TB, class BLayout,
class TC, class CLayout,
__CUTE_REQUIRES(DLayout::rank == 1 && is_rmem<TD>::value &&
ALayout::rank == 1 && is_rmem<TA>::value &&
BLayout::rank == 1 && is_rmem<TB>::value &&
CLayout::rank == 1 && is_rmem<TC>::value)>
CUTE_HOST_DEVICE
void
gemm(MMA_Atom<MMA> const& mma,
Tensor<TD, DLayout> & D, // (V) Logical data
Tensor<TA, ALayout> const& A, // (V) Logical data
Tensor<TB, BLayout> const& B, // (V) Logical data
Tensor<TC, CLayout> const& C) // (V) Logical data
{
// No static assertions on (V), MMA checks compatibility
mma.call(D, A, B, C);
}
// Dispatch [2]: (M) x (N) => (M,N)
template <class MMA,
class TD, class DLayout,
class TA, class ALayout,
class TB, class BLayout,
class TC, class CLayout,
__CUTE_REQUIRES(DLayout::rank == 2 && is_rmem<TD>::value &&
ALayout::rank == 1 && is_rmem<TA>::value &&
BLayout::rank == 1 && is_rmem<TB>::value &&
CLayout::rank == 2 && is_rmem<TC>::value)>
CUTE_HOST_DEVICE
void
gemm(MMA_Atom<MMA> const& mma,
Tensor<TD, DLayout> & D, // (M,N) Logical data
Tensor<TA, ALayout> const& A, // (M) Logical data
Tensor<TB, BLayout> const& B, // (N) Logical data
Tensor<TC, CLayout> const& C) // (M,N) Logical data
{
CUTE_STATIC_ASSERT_V(size<0>(A) == size<0>(C)); // AM == CM
CUTE_STATIC_ASSERT_V(size<0>(B) == size<1>(C)); // BN == CN
CUTE_STATIC_ASSERT_V(size<0>(C) == size<0>(D) && size<1>(C) == size<1>(D));
gemm(mma,
D, // (M,N)
make_tensor(A.data(), append<2>(A.layout())), // (M,1)
make_tensor(B.data(), append<2>(B.layout())), // (N,1)
C); // (M,N)
}
// Dispatch [3]: (M,K) x (N,K) => (M,N)
template <class MMA,
class TD, class DLayout,
class TA, class ALayout,
class TB, class BLayout,
class TC, class CLayout,
__CUTE_REQUIRES(DLayout::rank == 2 && is_rmem<TD>::value &&
ALayout::rank == 2 && is_rmem<TA>::value &&
BLayout::rank == 2 && is_rmem<TB>::value &&
CLayout::rank == 2 && is_rmem<TC>::value)>
CUTE_HOST_DEVICE
void
gemm(MMA_Atom<MMA> const& mma,
Tensor<TD, DLayout> & D, // (M,N) Logical data
Tensor<TA, ALayout> const& A, // (M,K) Logical data
Tensor<TB, BLayout> const& B, // (N,K) Logical data
Tensor<TC, CLayout> const& C) // (M,N) Logical data
{
CUTE_STATIC_ASSERT_V(size<0>(A) == size<0>(C)); // AM == CM
CUTE_STATIC_ASSERT_V(size<0>(B) == size<1>(C)); // BN == CN
CUTE_STATIC_ASSERT_V(size<1>(A) == size<1>(B)); // AK == BK
CUTE_STATIC_ASSERT_V(size<0>(C) == size<0>(D) && size<1>(C) == size<1>(D));
// Assert this is a 1-value MMA
CUTE_STATIC_ASSERT_V(size<1>(typename MMA_Atom<MMA>::LayoutC_TV{}) == Int<1>{});
CUTE_STATIC_ASSERT_V(size<1>(typename MMA_Atom<MMA>::LayoutA_TV{}) == Int<1>{});
CUTE_STATIC_ASSERT_V(size<1>(typename MMA_Atom<MMA>::LayoutB_TV{}) == Int<1>{});
gemm(mma,
make_tensor(D.data(), prepend<3>(D.layout())), // (1,M,N)
make_tensor(A.data(), prepend<3>(A.layout())), // (1,M,K)
make_tensor(B.data(), prepend<3>(B.layout())), // (1,N,K)
make_tensor(C.data(), prepend<3>(C.layout()))); // (1,M,N)
}
// Dispatch [4]: (V,M) x (V,N) => (V,M,N)
template <class MMA,
class TD, class DLayout,
class TA, class ALayout,
class TB, class BLayout,
class TC, class CLayout,
__CUTE_REQUIRES(DLayout::rank == 3 && is_rmem<TD>::value &&
ALayout::rank == 2 && is_rmem<TA>::value &&
BLayout::rank == 2 && is_rmem<TB>::value &&
CLayout::rank == 3 && is_rmem<TC>::value)>
CUTE_HOST_DEVICE
void
gemm(MMA_Atom<MMA> const& mma,
Tensor<TD, DLayout> & D, // (V,M,N) Logical data
Tensor<TA, ALayout> const& A, // (V,M) Logical data
Tensor<TB, BLayout> const& B, // (V,N) Logical data
Tensor<TC, CLayout> const& C) // (V,M,N) Logical data
{
CUTE_STATIC_ASSERT_V(size<1>(A) == size<1>(C)); // AM == CM
CUTE_STATIC_ASSERT_V(size<1>(B) == size<2>(C)); // BN == CN
CUTE_STATIC_ASSERT_V(size<0>(C) == size<0>(D) && size<1>(C) == size<1>(D) && size<2>(C) == size<2>(D));
auto M = size<1>(A);
auto N = size<1>(B);
// REGISTER .reuse OPTIMIZATIONS
// 64-bit traversal specialization -- serpentine path
if constexpr (decltype(size<0>(A))::value * sizeof(typename TA::value_type) == 8 &&
decltype(size<0>(B))::value * sizeof(typename TB::value_type) == 8)
{
#if 1 // NOTE: Row- vs Col- major could depend on the C-matrix order... (which we can test)
// Row-major serpentine iteration
CUTE_UNROLL
for (int m = 0; m < M; ++m) {
CUTE_UNROLL
for (int n = 0; n < N; ++n) {
int ns = (m & 1) ? N-1-n : n; // Serpentine coordinate
gemm(mma, D(_,m,ns), A(_,m), B(_,ns), C(_,m,ns));
}
}
#else
// Col-major serpentine iteration
CUTE_UNROLL
for (int n = 0; n < N; ++n) {
CUTE_UNROLL
for (int m = 0; m < M; ++m) {
int ms = (n & 1) ? M-1-m : m; // Serpentine coordinate
gemm(mma, D(_,ms,n), A(_,ms), B(_,n), C(_,ms,n));
}
}
#endif
} else
// 32-bit traversal specialization -- kinked serpentine path
if constexpr (decltype(size<0>(A))::value * sizeof(typename TA::value_type) == 4 &&
decltype(size<0>(B))::value * sizeof(typename TB::value_type) == 4)
{
#if 1 // NOTE: Row- vs Col- major could depend on the C-matrix order... (which we can test)
// Row-major kinked serpentine iteration
CUTE_UNROLL
for (int m = 0; m < M; m += 2) {
CUTE_UNROLL
for (int n = 0; n < N; ++n) {
int ns = (m & 2) ? N-1-n : n;
gemm(mma, D(_,m+0,ns), A(_,m+0), B(_,ns), C(_,m+0,ns));
if (m+1 < M) {
gemm(mma, D(_,m+1,ns), A(_,m+1), B(_,ns), C(_,m+1,ns));
}
}
}
#else
// Col-major kinked serpentine iteration
CUTE_UNROLL
for (int n = 0; n < N; n += 2) {
CUTE_UNROLL
for (int m = 0; m < M; ++m) {
// Kinked serpentine traversal for maximum register reuse
int ms = (n & 2) ? M-1-m : m;
gemm(mma, D(_,ms,n+0), A(_,ms), B(_,n+0), C(_,ms,n+0));
if (n+1 < N) {
gemm(mma, D(_,ms,n+1), A(_,ms), B(_,n+1), C(_,ms,n+1));
}
}
}
#endif
} else
// 64-bit + 32-bit traversal order -- keep A (64-bit) in the outer loop and serpentine B
if constexpr (decltype(size<0>(A))::value * sizeof(typename TA::value_type) == 8 &&
decltype(size<0>(B))::value * sizeof(typename TB::value_type) == 4) {
// Row-major serpentine iteration
CUTE_UNROLL
for (int m = 0; m < M; ++m) {
CUTE_UNROLL
for (int n = 0; n < N; ++n) {
int ns = (m & 1) ? N-1-n : n; // Serpentine coordinate
gemm(mma, D(_,m,ns), A(_,m), B(_,ns), C(_,m,ns));
}
}
} else
// 32-bit + 64-bit traversal order -- keep B (64-bit) in the outer loop and serpentine A
if constexpr (decltype(size<0>(A))::value * sizeof(typename TA::value_type) == 4 &&
decltype(size<0>(B))::value * sizeof(typename TB::value_type) == 8) {
// Col-major serpentine iteration
CUTE_UNROLL
for (int n = 0; n < N; ++n) {
CUTE_UNROLL
for (int m = 0; m < M; ++m) {
int ms = (n & 1) ? M-1-m : m; // Serpentine coordinate
gemm(mma, D(_,ms,n), A(_,ms), B(_,n), C(_,ms,n));
}
}
} else
// Fallback to serpentine loop
{
// Col-major serpentine iteration
CUTE_UNROLL
for (int n = 0; n < N; ++n) {
CUTE_UNROLL
for (int m = 0; m < M; ++m) {
int ms = (n & 1) ? M-1-m : m; // Serpentine coordinate
gemm(mma, D(_,ms,n), A(_,ms), B(_,n), C(_,ms,n));
}
}
}
}
// Dispatch [5]: (V,M,K) x (V,N,K) => (V,M,N)
template <class MMA,
class TD, class DLayout,
class TA, class ALayout,
class TB, class BLayout,
class TC, class CLayout,
__CUTE_REQUIRES(DLayout::rank == 3 && is_rmem<TD>::value &&
ALayout::rank == 3 && is_rmem<TA>::value &&
BLayout::rank == 3 && is_rmem<TB>::value &&
CLayout::rank == 3 && is_rmem<TC>::value)>
CUTE_HOST_DEVICE
void
gemm(MMA_Atom<MMA> const& mma,
Tensor<TD, DLayout> & D, // (V,M,N) Logical data
Tensor<TA, ALayout> const& A, // (V,M,K) Logical data
Tensor<TB, BLayout> const& B, // (V,N,K) Logical data
Tensor<TC, CLayout> const& C) // (V,M,N) Logical data
{
CUTE_STATIC_ASSERT_V(size<1>(A) == size<1>(C)); // AM == CM
CUTE_STATIC_ASSERT_V(size<1>(B) == size<2>(C)); // BN == CN
CUTE_STATIC_ASSERT_V(size<2>(A) == size<2>(B)); // AK == BK
CUTE_STATIC_ASSERT_V(size<0>(C) == size<0>(D) && size<1>(C) == size<1>(D) && size<2>(C) == size<2>(D));
auto K = size<2>(A);
CUTE_UNROLL
for (int k = 0; k < K; ++k) {
gemm(mma, D, A(_,_,k), B(_,_,k), C);
}
}
//
// Thread-Local Shared-Memory GEMMs
//
// Dispatch [1]: (V) x (V) => (V)
// Dispatch [2]: (M) x (N) => (M,N)
// Dispatch [3]: (M,K) x (N,K) => (M,N)
// Dispatch [4]: (V,M) x (V,N) => (V,M,N)
// Dispatch [5]: (V,M,K) x (V,N,K) => (V,M,N)
// Dispatch [3]: (M,K) x (N,K) => (M,N)
template <class MMA,
class TD, class DLayout,
class TA, class ALayout,
class TB, class BLayout,
class TC, class CLayout,
__CUTE_REQUIRES(DLayout::rank == 2 && is_rmem<TD>::value &&
ALayout::rank == 2 && is_smem<TA>::value &&
BLayout::rank == 2 && is_smem<TB>::value &&
CLayout::rank == 2 && is_rmem<TC>::value)>
CUTE_HOST_DEVICE
void
gemm(MMA_Atom<MMA> const& mma,
Tensor<TD, DLayout> & D, // (M,N) Logical data
Tensor<TA, ALayout> const& A, // (M,K) Logical data
Tensor<TB, BLayout> const& B, // (N,K) Logical data
Tensor<TC, CLayout> const& C) // (M,N) Logical data
{
CUTE_STATIC_ASSERT_V(size<0>(A) == size<0>(C)); // AM == CM
CUTE_STATIC_ASSERT_V(size<0>(B) == size<1>(C)); // BN == CN
CUTE_STATIC_ASSERT_V(size<1>(A) == size<1>(B)); // AK == BK
CUTE_STATIC_ASSERT_V(size<0>(C) == size<0>(D) && size<1>(C) == size<1>(D));
// Assert this is a 1-value MMA
CUTE_STATIC_ASSERT_V(size<1>(typename MMA_Atom<MMA>::LayoutC_TV{}) == Int<1>{});
CUTE_STATIC_ASSERT_V(size<1>(typename MMA_Atom<MMA>::LayoutA_TV{}) == Int<1>{});
CUTE_STATIC_ASSERT_V(size<1>(typename MMA_Atom<MMA>::LayoutB_TV{}) == Int<1>{});
gemm(mma,
make_tensor(D.data(), prepend<3>(D.layout())), // (1,M,N)
make_tensor(A.data(), prepend<3>(A.layout())), // (1,M,K)
make_tensor(B.data(), prepend<3>(B.layout())), // (1,N,K)
make_tensor(C.data(), prepend<3>(C.layout()))); // (1,M,N)
}
// Dispatch [5]: (V,M,K) x (V,N,K) => (V,M,N)
template <class MMA,
class TD, class DLayout,
class TA, class ALayout,
class TB, class BLayout,
class TC, class CLayout,
__CUTE_REQUIRES(DLayout::rank == 3 && is_rmem<TD>::value &&
ALayout::rank == 3 && is_smem<TA>::value &&
BLayout::rank == 3 && is_smem<TB>::value &&
CLayout::rank == 3 && is_rmem<TC>::value)>
CUTE_HOST_DEVICE
void
gemm(MMA_Atom<MMA> const& mma,
Tensor<TD, DLayout> & D, // (V,M,N) Logical data
Tensor<TA, ALayout> const& A, // (V,M,K) Logical data
Tensor<TB, BLayout> const& B, // (V,N,K) Logical data
Tensor<TC, CLayout> const& C) // (V,M,N) Logical data
{
CUTE_STATIC_ASSERT_V(size<1>(A) == size<1>(C)); // AM == CM
CUTE_STATIC_ASSERT_V(size<1>(B) == size<2>(C)); // BN == CN
CUTE_STATIC_ASSERT_V(size<2>(A) == size<2>(B)); // AK == BK
CUTE_STATIC_ASSERT_V(size<0>(C) == size<0>(D) && size<1>(C) == size<1>(D) && size<2>(C) == size<2>(D));
auto rA = MMA_Atom<MMA>::make_fragment_A(A);
auto rB = MMA_Atom<MMA>::make_fragment_B(B);
auto K = size<2>(A);
CUTE_UNROLL
for (int k = 0; k < K; ++k)
{
copy(A(_,_,k), rA(_,_,k));
copy(B(_,_,k), rB(_,_,k));
// Thread-level register gemm for k
gemm(mma, D, rA(_,_,k), rB(_,_,k), C);
}
}
//
// Collective Shared-Memory GEMMs
//
template <class... Args,
class Alpha, class TA, class ALayout, class TB, class BLayout,
class Beta, class TC, class CLayout,
class ALoadTransformOp, class BLoadTransformOp,
__CUTE_REQUIRES(ALayout::rank == 2 && is_smem<TA>::value &&
BLayout::rank == 2 && is_smem<TB>::value &&
CLayout::rank == 2 && is_smem<TC>::value)>
CUTE_HOST_DEVICE
void
gemm(ThrMMA<Args...> const& thr_mma,
Alpha const& alpha,
Tensor<TA, ALayout> sA,
Tensor<TB, BLayout> sB,
Beta const& beta,
Tensor<TC, CLayout> sC,
ALoadTransformOp const& sA_load_op /* transforms A values before used in GEMM */,
BLoadTransformOp const& sB_load_op /* transforms B values before used in GEMM */)
{
CUTE_STATIC_ASSERT_V(size<0>(sA) == size<0>(sC)); // AM == CM
CUTE_STATIC_ASSERT_V(size<0>(sB) == size<1>(sC)); // BN == CN
CUTE_STATIC_ASSERT_V(size<1>(sA) == size<1>(sB)); // AK == BK
using TypeA = typename TA::value_type;
using TypeB = typename TB::value_type;
using TypeC = typename TC::value_type;
static_assert(is_same_v<decay_t<invoke_result_t<ALoadTransformOp, TypeA>>, TypeA>,
"ALoadTransformOp functor must accept and return value of type TA::value_type");
static_assert(is_same_v<decay_t<invoke_result_t<BLoadTransformOp, TypeB>>, TypeB>,
"BLoadTransformOp functor must accept and return value of type TB::value_type");
// Original, static size of the problem
auto M = size<0>(sC);
auto N = size<1>(sC);
auto K = size<1>(sA);
// Block size of the compute tile
auto BLK_M = tile_size<0>(thr_mma);
auto BLK_N = tile_size<1>(thr_mma);
auto BLK_K = tile_size<2>(thr_mma);
// Compute the "residues"
auto m_residue = M - BLK_M * (ceil_div(M, BLK_M) - Int<1>{}); // (0,BLK_M]
auto n_residue = N - BLK_N * (ceil_div(N, BLK_N) - Int<1>{}); // (0,BLK_N]
auto k_residue = K - BLK_K * (ceil_div(K, BLK_K) ); // (-BLK_K,0]
// Shift the origin so k_residue is zeroth tile
sA.data() = &sA(0,k_residue);
sB.data() = &sB(0,k_residue);
#if 0
if (thread0()) {
printf("%d in BLK_M (%d)\n", int(m_residue), int(BLK_M));
printf("%d in BLK_N (%d)\n", int(n_residue), int(BLK_N));
printf("%d in BLK_K (%d)\n", int(k_residue), int(BLK_K));
}
#endif
//
// MMA Partitioning
//
// Round the layout extents up to BLK_X
Tensor rounded_sA = sA.compose(make_shape(ceil_div(M, BLK_M) * BLK_M, ceil_div(K, BLK_K) * BLK_K));
Tensor rounded_sB = sB.compose(make_shape(ceil_div(N, BLK_N) * BLK_N, ceil_div(K, BLK_K) * BLK_K));
Tensor rounded_sC = sC.compose(make_shape(ceil_div(M, BLK_M) * BLK_M, ceil_div(N, BLK_N) * BLK_N));
#if 0
if (thread0()) {
print(rounded_sA.layout()); print("\n");
print(rounded_sB.layout()); print("\n");
print(rounded_sC.layout()); print("\n");
}
#endif
// Partition the sA and sB tiles across the threads for the MMA
Tensor tCsA = thr_mma.partition_A(rounded_sA); // (MMA,MMA_M,MMA_K)
Tensor tCsB = thr_mma.partition_B(rounded_sB); // (MMA,MMA_N,MMA_K)
Tensor tCsC = thr_mma.partition_C(rounded_sC); // (MMA,MMA_M,MMA_N)
// Create register tensors for the MMA to operate on
Tensor tCrA = thr_mma.make_fragment_A(tCsA); // (MMA,MMA_M,MMA_K)
Tensor tCrB = thr_mma.make_fragment_B(tCsB); // (MMA,MMA_N,MMA_K)
Tensor tCrC = thr_mma.make_fragment_C(tCsC); // (MMA,MMA_M,MMA_N)
#if 0
if (thread0()) {
print(tCsA.layout()); print("\n");
print(tCsB.layout()); print("\n");
print(tCsC.layout()); print("\n");
print(tCrA.layout()); print("\n");
print(tCrB.layout()); print("\n");
print(tCrC.layout()); print("\n");
}
#endif
//
// PREDICATION
//
// Allocate the preds for only the MMA-mode of tCsA and tCsB
Tensor tCpA = make_tensor<bool>(size<0>(tCsA));
Tensor tCpB = make_tensor<bool>(size<0>(tCsB));
// Create coordinate tensors on a single compute block for predication
Tensor cA = make_identity_tensor(make_shape(BLK_M, BLK_K)); // (BLK_M,BLK_K) -> (blk_m,blk_k)
Tensor cB = make_identity_tensor(make_shape(BLK_N, BLK_K)); // (BLK_M,BLK_K) -> (blk_n,blk_k)
// Repeat partitioning with thr_mma
Tensor tCcA = thr_mma.partition_A(cA); // (MMA,1,1) -> (blk_m,blk_k)
Tensor tCcB = thr_mma.partition_B(cB); // (MMA,1,1) -> (blk_n,blk_k)
// Populate the m and n predicates
CUTE_UNROLL
for (int i = 0; i < size(tCpA); ++i) {
tCpA(i) = elem_less(get<0>(tCcA(i)), m_residue);
}
CUTE_UNROLL
for (int i = 0; i < size(tCpB); ++i) {
tCpB(i) = elem_less(get<0>(tCcB(i)), n_residue);
}
#if 0
printf("Thr %d: A(%d,%d):%d B(%d,%d):%d\n",
threadIdx.x,
int(get<0>(tCcA(0))), int(get<1>(tCcA(0))), int(tCpA(0)),
int(get<0>(tCcB(0))), int(get<1>(tCcB(0))), int(tCpB(0)));
#endif
//
// PREFETCH k_block = 0 (with k-predication)
//
CUTE_UNROLL
for (int i = 0; i < size<0>(tCsA); ++i) { // Copy MMA_I
if (k_residue == 0 || get<1>(tCcA(i)) >= -k_residue) { // k_block = 0, predicated on k
CUTE_UNROLL
for (int m = 0; m < size<1>(tCsA); ++m) { // Copy MMA_M, predicated on m
tCrA(i,m,0) = (m_residue == BLK_M || m < size<1>(tCsA)-1 || tCpA(i)) ? sA_load_op(tCsA(i,m,0)) : TypeA{};
}
}
}
CUTE_UNROLL
for (int i = 0; i < size<0>(tCsB); ++i) { // Copy MMA_I
if (k_residue == 0 || get<1>(tCcB(i)) >= -k_residue) { // k_block = 0, predicated on k
CUTE_UNROLL
for (int n = 0; n < size<1>(tCsB); ++n) { // Copy MMA_N, predicated on n
tCrB(i,n,0) = (n_residue == BLK_N || n < size<1>(tCsB)-1 || tCpB(i)) ? sB_load_op(tCsB(i,n,0)) : TypeB{};
}
}
}
//
// MAINLOOP
//
// Clear accumulators
clear(tCrC);
constexpr int K_BLOCK_MAX = size<2>(tCrA);
CUTE_UNROLL
for (int k_block = 0; k_block < K_BLOCK_MAX; ++k_block)
{
// static-if load the next k_block. No k-predication required on these loads.
if (k_block < K_BLOCK_MAX-1)
{
// Load the next k_block
int k_next = k_block + 1;
CUTE_UNROLL
for (int m = 0; m < size<1>(tCsA); ++m) { // Copy MMA_M
CUTE_UNROLL
for (int i = 0; i < size<0>(tCsA); ++i) { // Copy_if MMA_I predicated on m
tCrA(i,m,k_next) = (m_residue == BLK_M || m < size<1>(tCsA)-1 || tCpA(i)) ? sA_load_op(tCsA(i,m,k_next)) : TypeA{};
}
}
CUTE_UNROLL
for (int n = 0; n < size<1>(tCsB); ++n) { // Copy MMA_N
CUTE_UNROLL
for (int i = 0; i < size<0>(tCsB); ++i) { // Copy MMA_I predicated on n
tCrB(i,n,k_next) = (n_residue == BLK_N || n < size<1>(tCsB)-1 || tCpB(i)) ? sB_load_op(tCsB(i,n,k_next)) : TypeB{};
}
}
}
// GEMM on k_block in registers
gemm(thr_mma, tCrA(_,_,k_block), tCrB(_,_,k_block), tCrC);
}
//
// Epilogue
//
Tensor cC = make_identity_tensor(make_shape(BLK_M, BLK_N)); // (BLK_M,BLK_N) -> (blk_m,blk_n)
Tensor tCcC = thr_mma.partition_C(cC); // (MMA, 1, 1) -> (blk_m,blk_n)
const bool isBetaZero = (beta == Beta{});
// Custom axpby_if for now
CUTE_UNROLL
for (int m = 0; m < size<1>(tCsC); ++m)
{
CUTE_UNROLL
for (int n = 0; n < size<2>(tCsC); ++n)
{
CUTE_UNROLL
for (int i = 0; i < size<0>(tCsC); ++i)
{
if ((m_residue == BLK_M || m < size<1>(tCrC)-1 || get<0>(tCcC(i)) < m_residue) &&
(n_residue == BLK_N || n < size<2>(tCrC)-1 || get<1>(tCcC(i)) < n_residue))
{
tCsC(i,m,n) = isBetaZero ? alpha * tCrC(i,m,n) : alpha * tCrC(i,m,n) + beta * tCsC(i,m,n);
}
}
}
}
}
template <class... Args,
class Alpha, class TA, class ALayout, class TB, class BLayout,
class Beta, class TC, class CLayout,
__CUTE_REQUIRES(ALayout::rank == 2 && is_smem<TA>::value &&
BLayout::rank == 2 && is_smem<TB>::value &&
CLayout::rank == 2 && is_smem<TC>::value)>
CUTE_HOST_DEVICE
void
gemm(ThrMMA<Args...> const& thr_mma,
Alpha const& alpha,
Tensor<TA, ALayout> sA,
Tensor<TB, BLayout> sB,
Beta const& beta,
Tensor<TC, CLayout> sC)
{
gemm(thr_mma, alpha, sA, sB, beta, sC, identity() /* sA_load_op */, identity() /* sB_load_op */);
}
} // end namespace cute