Files
clang-p2996/mlir/lib/Dialect/NVGPU/IR/NVGPUDialect.cpp
Christopher Bate 708185f03f [mlir][NVGPU] Add support for structured sparsity MMA variants
This change adds a new NVGPU operation that targets the PTX `mma.sp.sync`
instruction variants. A lowering to NVVM is provided using inline
assembly.

Reviewed By: ThomasRaoux, manishucsd

Differential Revision: https://reviews.llvm.org/D137202
2022-11-07 09:43:03 -07:00

288 lines
11 KiB
C++

//===- NVGPUDialect.cpp - MLIR NVGPU ops implementation -------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements the NVGPU dialect and its operations.
//
//===----------------------------------------------------------------------===//
#include "mlir/Dialect/NVGPU/IR/NVGPUDialect.h"
#include "mlir/Dialect/GPU/IR/GPUDialect.h"
#include "mlir/IR/Builders.h"
#include "mlir/IR/BuiltinAttributes.h"
#include "mlir/IR/DialectImplementation.h"
#include "mlir/IR/OpImplementation.h"
#include "mlir/IR/TypeUtilities.h"
#include "mlir/IR/Verifier.h"
#include "llvm/ADT/TypeSwitch.h"
using namespace mlir;
using namespace mlir::nvgpu;
void nvgpu::NVGPUDialect::initialize() {
addTypes<
#define GET_TYPEDEF_LIST
#include "mlir/Dialect/NVGPU/IR/NVGPUTypes.cpp.inc"
>();
addOperations<
#define GET_OP_LIST
#include "mlir/Dialect/NVGPU/IR/NVGPU.cpp.inc"
>();
}
//===----------------------------------------------------------------------===//
// NVGPU_DeviceAsyncCopyOp
//===----------------------------------------------------------------------===//
/// Return true if the last dimension of the MemRefType has unit stride. Also
/// return true for memrefs with no strides.
static bool isLastMemrefDimUnitStride(MemRefType type) {
int64_t offset;
SmallVector<int64_t> strides;
if (failed(getStridesAndOffset(type, strides, offset))) {
return false;
}
return strides.back() == 1;
}
LogicalResult DeviceAsyncCopyOp::verify() {
auto srcMemref = getSrc().getType().cast<MemRefType>();
auto dstMemref = getDst().getType().cast<MemRefType>();
unsigned workgroupAddressSpace = gpu::GPUDialect::getWorkgroupAddressSpace();
if (!isLastMemrefDimUnitStride(srcMemref))
return emitError("source memref most minor dim must have unit stride");
if (!isLastMemrefDimUnitStride(dstMemref))
return emitError("destination memref most minor dim must have unit stride");
if (dstMemref.getMemorySpaceAsInt() != workgroupAddressSpace)
return emitError("destination memref must have memory space ")
<< workgroupAddressSpace;
if (dstMemref.getElementType() != srcMemref.getElementType())
return emitError("source and destination must have the same element type");
if (size_t(srcMemref.getRank()) != getSrcIndices().size())
return emitOpError() << "expected " << srcMemref.getRank()
<< " source indices, got " << getSrcIndices().size();
if (size_t(dstMemref.getRank()) != getDstIndices().size())
return emitOpError() << "expected " << dstMemref.getRank()
<< " destination indices, got "
<< getDstIndices().size();
return success();
}
//===----------------------------------------------------------------------===//
// NVGPU_MmaSyncOp
//===----------------------------------------------------------------------===//
void MmaSyncOp::build(::mlir::OpBuilder &odsBuilder,
::mlir::OperationState &odsState, Value matrixA,
Value matrixB, Value matrixC, ArrayAttr mmaShape) {
build(odsBuilder, odsState, matrixC.getType(), matrixA, matrixB, matrixC,
mmaShape, UnitAttr());
}
/// Performs verification for MmaSyncOp and MmaSparseSyncOp.
static LogicalResult verifyMmaSyncOp(Operation *op,
TypedValue<VectorType> matrixA,
TypedValue<VectorType> matrixB,
TypedValue<VectorType> matrixC,
const std::array<int64_t, 3> &mmaShape,
bool tf32Enabled, bool sparse = false) {
// The verification for mma.sync covering various shapes and data types is
// based on the fundamental tensor core shape.
// "Fundamental" tensor core shapes:
// - For F32 (TF32), F16, S8, and S4 data
// types the fundamental tensor core operation is of shape 8-by-8-by-128b.
// - F64 is an exception and is of shape 8-by-8-by-256b.
constexpr int kThreads = 32; // 32 threads per warp
int64_t shapeM = 8;
int64_t shapeN = 8;
int64_t shapeK; // set based on data type (128b for all data types except F64)
// Number of elements A, B, and C per thread per fundamental tensor core tile
int64_t numElementA; // set based on data type (32b except F64)
int64_t numElementB; // set based on data type (32b except F64)
int64_t numElementC{2}; // two accumulator elements per fundamental tile
// nvgpu.mma.sync vector operands (per thread)
auto aVector = matrixA.getType();
auto bVector = matrixB.getType();
auto cVector = matrixC.getType();
// vector shapes
ArrayRef<int64_t> aShape = aVector.getShape();
ArrayRef<int64_t> bShape = bVector.getShape();
ArrayRef<int64_t> cShape = cVector.getShape();
// vector element type
Type aType = aVector.getElementType();
// Certain data types are not allowed in sparse mode.
if (sparse && aType.isF64())
return op->emitError() << "f64 is not supported for sparse mode";
if (aType.isF64()) {
// exception to 8-by-8-128b fundamental tensor core tile size
shapeK = 4;
numElementA = 1;
numElementB = 1;
} else if (aType.isF32() || aType.isBF16() || aType.isF16() ||
aType.isInteger(8) || aType.isInteger(4)) {
// 8-by-8-128b fundamental tensor core tile size
int operandBitwidth = aType.getIntOrFloatBitWidth();
shapeK = 128 / operandBitwidth; // 128b wide shapeK
numElementA = 32 / operandBitwidth; // 32b wide operand A
numElementB = 32 / operandBitwidth; // 32b wide operand B
} else {
return op->emitError()
<< "expected input data type (i4,i8,f16,bf16,tf32,f64) "
"supported by "
<< op->getName();
}
//
// Basic verification
//
auto [m, n, k] = mmaShape;
// verify warp-wide size for vector a
int64_t sparseFactor = sparse ? 2 : 1;
if (aShape[0] * aShape[1] * kThreads != m * k / sparseFactor)
return op->emitOpError()
<< "expected " << m * k << " warp-wide matrix A elements";
// verify warp-wide size for vector b
if (bShape[0] * bShape[1] * kThreads != k * n)
return op->emitOpError()
<< "expected " << k * n << " warp-wide matrix B elements";
// verify warp-wide size for vector c
if (cShape[0] * cShape[1] * kThreads != m * n)
return op->emitOpError()
<< "expected " << m * n << " warp-wide matrix C elements";
// verify tf32 tensor cores are enabled for only F32 datatype
if (tf32Enabled && !(aType.isF32()))
return op->emitOpError()
<< "expected tf32 tensor cores only for F32 operands";
//
// Extended verification
//
// tiles of fundamental tensor core operations
int64_t mTile = m / shapeM;
int64_t nTile = n / shapeN;
int64_t kTile = k / shapeK;
// verify shape of aVector
if ((aShape[0] != mTile * kTile / (sparse ? 2 : 1)) ||
(aShape[1] != numElementA))
return op->emitOpError() << "expected matrix A to be shaped ("
<< mTile * kTile << " x " << numElementA << ")";
// verify shape of bVector
if ((bShape[0] != kTile * nTile) || (bShape[1] != numElementB))
return op->emitOpError() << "expected matrix B to be shaped ("
<< kTile * nTile << " x " << numElementB << ")";
// verify shape of cVector
if ((cShape[0] != mTile * nTile) || (cShape[1] != numElementC))
return op->emitOpError() << "expected matrix C to be shaped ("
<< mTile * nTile << " x " << numElementC << ")";
return success();
}
LogicalResult MmaSyncOp::verify() {
return verifyMmaSyncOp(this->getOperation(), getMatrixA(), getMatrixB(),
getMatrixC(), getMmaShapeAsArray(),
getOperation()->hasAttr(getTf32EnabledAttrName()));
}
//===----------------------------------------------------------------------===//
// NVGPU_MmaSparseSyncOp
//===----------------------------------------------------------------------===//
void MmaSparseSyncOp::build(::mlir::OpBuilder &odsBuilder,
::mlir::OperationState &odsState, Value matrixA,
Value matrixB, Value matrixC, Value sparseMetadata,
ArrayRef<int64_t> mmaShape) {
build(odsBuilder, odsState, matrixC.getType(), matrixA, matrixB, matrixC,
sparseMetadata, odsBuilder.getI64ArrayAttr(mmaShape), 0, UnitAttr());
}
LogicalResult MmaSparseSyncOp::verify() {
return verifyMmaSyncOp(this->getOperation(), getMatrixA(), getMatrixB(),
getMatrixC(), getMmaShapeAsArray(),
getOperation()->hasAttr(getTf32EnabledAttrName()),
true);
}
//===----------------------------------------------------------------------===//
// NVGPU_LdMatrixOp
//===----------------------------------------------------------------------===//
LogicalResult LdMatrixOp::verify() {
// ldmatrix reads data from source in shared memory
auto srcMemref = getSrcMemref().getType().cast<MemRefType>();
// ldmatrix writes data to result/destination in vector registers
auto resVector = getRes().getType().cast<VectorType>();
// vector register shape, element type, and bitwidth
ArrayRef<int64_t> resShape = resVector.getShape();
Type resType = resVector.getElementType();
int64_t elementBitWidth = resType.getIntOrFloatBitWidth();
// ldmatrix loads 32 bits into vector registers per 8-by-8 tile per thread
int64_t numElementsPer32b = 32 / elementBitWidth;
// number of 8-by-8 tiles
int64_t numTiles = getNumTiles();
// transpose elements in vector registers at 16b granularity when true
bool isTranspose = getTranspose();
// address space id for shared memory
unsigned smemAddressSpace = gpu::GPUDialect::getWorkgroupAddressSpace();
//
// verification
//
if (!(srcMemref.getMemorySpaceAsInt() == smemAddressSpace))
return emitError()
<< "expected nvgpu.ldmatrix srcMemref must have memory space "
<< smemAddressSpace;
if (elementBitWidth > 32)
return emitError() << "nvgpu.ldmatrix works for 32b or lower";
if (isTranspose && !(elementBitWidth == 16))
return emitError()
<< "nvgpu.ldmatrix transpose works only at 16b granularity";
if (!(resShape[1] == numElementsPer32b))
return emitError() << "expected vector register shape[1] = "
<< numElementsPer32b;
if (!(resShape[0] == numTiles))
return emitError()
<< "expected vector register shape[0] and numTiles to match";
return success();
}
//===----------------------------------------------------------------------===//
// TableGen'd dialect, type, and op definitions
//===----------------------------------------------------------------------===//
#include "mlir/Dialect/NVGPU/IR/NVGPUDialect.cpp.inc"
#define GET_OP_CLASSES
#include "mlir/Dialect/NVGPU/IR/NVGPU.cpp.inc"
#define GET_TYPEDEF_CLASSES
#include "mlir/Dialect/NVGPU/IR/NVGPUTypes.cpp.inc"