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triton/include/triton/Dialect/TritonGPU/IR/TritonGPUAttrDefs.td
2022-12-09 19:31:34 -08:00

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#ifndef TRITONGPU_ATTRDEFS
#define TRITONGPU_ATTRDEFS
include "triton/Dialect/TritonGPU/IR/TritonGPUDialect.td"
include "triton/Dialect/Triton/IR/TritonInterfaces.td"
//===----------------------------------------------------------------------===//
// TritonGPU Attribute Definitions
//===----------------------------------------------------------------------===//
class TritonGPU_Attr<string name, list<Trait> traits = [],
string baseCppClass = "::mlir::Attribute">
: AttrDef<TritonGPU_Dialect, name, traits, baseCppClass> {
let description = [{
TritonGPU Tensors differ from usual tensors in that they contain a _layout_ attribute which determines
how the data should be partitioned across CUDA threads. Formally speaking, we define a layout as a function
\mathcal{L} that maps a multi-dimensional tensor index $i \in \mathbb{Z}^d$ to a set of integers T corresponding
to the indices of the CUDA threads allowed to access some data at index $i$.
For example, let us consider the layout function:
\mathcal{L}(0, 0) = {0, 4}
\mathcal{L}(0, 1) = {1, 5}
\mathcal{L}(1, 0) = {2, 6}
\mathcal{L}(1, 1) = {3, 7}
Then, attaching $\mathcal{L} to a tensor $T$ would mean that:
- T[0,0] is owned by both cuda thread 0 and 4
- T[0,1] is owned by both cuda thread 1 and 5
- T[1,0] is owned by both cuda thread 2 and 6
- T[1,1] is owned by both cuda thread 3 and 7
Right now, Triton implements two classes of layouts: shared, and distributed.
}];
code extraBaseClassDeclaration = [{
unsigned getElemsPerThread(ArrayRef<int64_t> shape) const;
::mlir::LogicalResult verifyLayoutForArg(::mlir::Operation* op, unsigned argNo) const;
}];
}
//===----------------------------------------------------------------------===//
// Shared Layout Encoding
//===----------------------------------------------------------------------===//
def SharedEncodingAttr : TritonGPU_Attr<"SharedEncoding"> {
let mnemonic = "shared";
let description = [{
An encoding for tensors whose elements may be simultaneously accessed by
different cuda threads in the programs, via shared memory. In other words,
for all indices i \in R^d, \mathcal{L}(i) = {0, 1, ..., 32*num_warps - 1}.
In order to avoid shared memory bank conflicts, elements may be swizzled
in memory. For example, a swizzled row-major layout could store its data
as follows:
A_{0, 0} A_{0, 1} A_{0, 2} A_{0, 3} ... [phase 0] \ per_phase = 2
A_{1, 0} A_{1, 1} A_{1, 2} A_{1, 3} ... [phase 0] /
groups of vec=2 elements
are stored contiguously
_ _ _ _ /\_ _ _ _
A_{2, 2} A_{2, 3} A_{2, 0} A_{2, 1} ... [phase 1] \ per phase = 2
A_{3, 2} A_{3, 3} A_{3, 0} A_{3, 1} ... [phase 1] /
}];
let parameters = (
ins
// swizzle info
"unsigned":$vec, "unsigned":$perPhase, "unsigned":$maxPhase,
ArrayRefParameter<"unsigned", "order of axes by the rate of changing">:$order
);
let builders = [
AttrBuilder<(ins "DotOperandEncodingAttr":$dotOpEnc,
"ArrayRef<int64_t>":$shape,
"ArrayRef<unsigned>":$order,
"Type":$eltTy), [{
auto mmaEnc = dotOpEnc.getParent().dyn_cast<MmaEncodingAttr>();
if(!mmaEnc)
return $_get(context, 1, 1, 1, order);
int version = mmaEnc.getVersion();
int opIdx = dotOpEnc.getOpIdx();
// number of rows per phase
int perPhase = 128 / (shape[order[0]] * (eltTy.getIntOrFloatBitWidth() / 8));
perPhase = std::max<int>(perPhase, 1);
// index of the inner dimension in `order`
unsigned inner = (opIdx == 0) ? 0 : 1;
// ---- begin version 1 ----
if (version == 1) {
bool is_row = order[0] != 0;
bool is_vec4 = opIdx == 0 ? !is_row && (shape[order[0]] <= 16) :
is_row && (shape[order[0]] <= 16);
// TODO[Superjomn]: Support the case when is_vec4=false later
// Currently, we only support ld.v2, for the mma layout varies with different ld vector width.
is_vec4 = true;
int pack_size = opIdx == 0 ? ((is_row || is_vec4) ? 1 : 2) :
((is_row && !is_vec4) ? 2 : 1);
int rep = 2 * pack_size;
int maxPhase = (order[inner] == 1 ? 8 : 4) / perPhase;
int vec = 2 * rep;
return $_get(context, vec, perPhase, maxPhase, order);
}
// ---- begin version 2 ----
if (version == 2) {
std::vector<size_t> matShape = {8, 8,
2 * 64 / eltTy.getIntOrFloatBitWidth()};
// for now, disable swizzle when using transposed int8 tensor cores
if (eltTy.isInteger(8) && order[0] == inner)
return $_get(context, 1, 1, 1, order);
// --- handle A operand ---
if (opIdx == 0) { // compute swizzling for A operand
int vec = (order[0] == 1) ? matShape[2] : matShape[0]; // k : m
int mmaStride = (order[0] == 1) ? matShape[0] : matShape[2];
int maxPhase = mmaStride / perPhase;
return $_get(context, vec, perPhase, maxPhase, order);
}
// --- handle B operand ---
if (opIdx == 1) {
int vec = (order[0] == 1) ? matShape[1] : matShape[2]; // n : k
int mmaStride = (order[0] == 1) ? matShape[2] : matShape[1];
int maxPhase = mmaStride / perPhase;
return $_get(context, vec, perPhase, maxPhase, order);
}
llvm_unreachable("invalid operand index");
}
// ---- not implemented ----
llvm_unreachable("unsupported swizzling for provided MMA version");
}]>
];
let extraClassDeclaration = extraBaseClassDeclaration;
}
//===----------------------------------------------------------------------===//
// Distributed Layout Encoding
//===----------------------------------------------------------------------===//
class DistributedEncoding<string name> : TritonGPU_Attr<name> {
let description = [{
Distributed encodings have a layout function that is entirely characterized
by a d-dimensional tensor L. Note that L doesn't need to have the same shape
(or even the same rank) as the tensor it is encoding.
The layout function \mathcal{L} of this layout is then defined, for an
index `i` \in R^D, as follows:
\mathcal{L}(A)[i_d] = L[(i_d + k_d*A.shape[d]) % L.shape[d]] \forall k_d such as i_d + k_d*A.shape[d] < L.shape[d]
For example, for a tensor/layout pair
A = [x x x x x x x x]
[x x x x x x x x]
L = [0 1 2 3 ]
[4 5 6 7 ]
[8 9 10 11]
[12 13 14 15]
Then the data of A would be distributed as follow between the 16 CUDA threads:
L(A) = [ {0,8} , {1,9} , {2,10}, {3,11}, {0,8} , {1, 9} , {2, 10}, {3, 11},
{4,12}, {5,13}, {6,14}, {7,15}, {4,12}, {5, 13}, {6, 14}, {7, 15} ]
}];
let extraClassDeclaration = extraBaseClassDeclaration;
}
//===----------------------------------------------------------------------===//
// Blocked Layout Encoding
//===----------------------------------------------------------------------===//
def BlockedEncodingAttr : DistributedEncoding<"BlockedEncoding"> {
let mnemonic = "blocked";
let description = [{
An encoding where each warp owns a contiguous portion of the target tensor. This is typically the kind of data layout
used to promote memory coalescing in LoadInst and StoreInst.
It is characterized by three tuples -- thread tile size, warp tile size, and block tile size -- which
specify the amount of elements owned by each CUDA thread, warp and CTA respectively.
For example, a row-major coalesced layout may partition a 16x16 tensor over 2 warps (i.e. 64 threads) as follows.
[ 0 0 1 1 2 2 3 3 ; 32 32 33 33 34 34 35 35 ]
[ 0 0 1 1 2 2 3 3 ; 32 32 33 33 34 34 35 35 ]
[ 4 4 5 5 6 6 7 7 ; 36 36 37 37 38 38 39 39 ]
[ 4 4 5 5 6 6 7 7 ; 36 36 37 37 38 38 39 39 ]
...
[ 28 28 29 29 30 30 31 31 ; 60 60 61 61 62 62 63 63 ]
[ 28 28 29 29 30 30 31 31 ; 60 60 61 61 62 62 63 63 ]
for
#triton_gpu.blocked_layout<{
sizePerThread = {2, 2}
threadsPerWarp = {8, 4}
warpsPerCTA = {1, 2}
}>
}];
let builders = [
// Custom builder initializes sizePerWarp and sizePerCTA automatically
// TODO: compiles on MacOS but not linux?
// AttrBuilder<(ins "ArrayRef<unsigned>":$sizePerThread,
// "ArrayRef<unsigned>":$threadsPerWarp,
// "ArrayRef<unsigned>":$warpsPerCTA,
// "ArrayRef<unsigned>":$order), [{
// int rank = threadsPerWarp.size();
// SmallVector<unsigned, 4> sizePerWarp(rank);
// SmallVector<unsigned, 4> sizePerCTA(rank);
// for (unsigned i = 0; i < rank; i++) {
// sizePerWarp.push_back(sizePerThread[i] * threadsPerWarp[i]);
// sizePerCTA.push_back(sizePerWarp[i] * warpsPerCTA[i]);
// }
// return $_get(context, sizePerThread, threadsPerWarp, warpsPerCTA, order, sizePerWarp, sizePerCTA);
// }]>,
// Custom builder initializes sizePerWarp and sizePerCTA automatically
// Default builder takes sizePerThread, order and numWarps, and tries to
// pack numWarps*32 threads in the provided order for use in a type
// of the given shape.
AttrBuilder<(ins "ArrayRef<int64_t>":$shape,
"ArrayRef<unsigned>":$sizePerThread,
"ArrayRef<unsigned>":$order,
"unsigned":$numWarps), [{
int rank = sizePerThread.size();
unsigned remainingLanes = 32;
unsigned remainingThreads = numWarps*32;
unsigned remainingWarps = numWarps;
unsigned prevLanes = 1;
unsigned prevWarps = 1;
SmallVector<unsigned, 4> threadsPerWarp(rank);
SmallVector<unsigned, 4> warpsPerCTA(rank);
for (int _dim = 0; _dim < rank - 1; ++_dim) {
int i = order[_dim];
unsigned threadsPerCTA = std::clamp<unsigned>(remainingThreads, 1, shape[i] / sizePerThread[i]);
threadsPerWarp[i] = std::clamp<unsigned>(threadsPerCTA, 1, remainingLanes);
warpsPerCTA[i] = std::clamp<unsigned>(threadsPerCTA / threadsPerWarp[i], 1, remainingWarps);
remainingWarps /= warpsPerCTA[i];
remainingLanes /= threadsPerWarp[i];
remainingThreads /= threadsPerCTA;
prevLanes *= threadsPerWarp[i];
prevWarps *= warpsPerCTA[i];
}
// Expand the last dimension to fill the remaining lanes and warps
threadsPerWarp[order[rank-1]] = 32 / prevLanes;
warpsPerCTA[order[rank-1]] = numWarps / prevWarps;
return $_get(context, sizePerThread, threadsPerWarp, warpsPerCTA, order);
}]>
];
let extraClassDeclaration = extraBaseClassDeclaration # [{
SliceEncodingAttr squeeze(int axis);
}];
let parameters = (
ins
ArrayRefParameter<"unsigned">:$sizePerThread,
ArrayRefParameter<"unsigned">:$threadsPerWarp,
ArrayRefParameter<"unsigned">:$warpsPerCTA,
// fastest-changing axis first
ArrayRefParameter<
"unsigned",
"order of axes by the rate of changing"
>:$order
// These attributes can be inferred from the rest
// ArrayRefParameter<"unsigned">:$sizePerWarp,
// ArrayRefParameter<"unsigned">:$sizePerCTA
);
}
//===----------------------------------------------------------------------===//
// MMA Layout Encoding
//===----------------------------------------------------------------------===//
// TODO: MMAv1 and MMAv2 should be two instances of the same class
def MmaEncodingAttr : DistributedEncoding<"MmaEncoding"> {
let mnemonic = "mma";
let description = [{
An encoding for tensors that have been produced by tensor cores.
It is characterized by two parameters:
- A 'version' which specifies the generation the tensor cores
whose output is being partitioned: 1 for first-gen tensor cores (Volta),
and 2 for second-gen tensor cores (Turing/Ampere).
- A `blockTileSize` to indicate how data should be
partitioned between warps.
// -------------------------------- version = 1 --------------------------- //
For first-gen tensor cores, the implicit warpTileSize is [16, 16].
Note: the layout is different from the recommended in PTX ISA
https://docs.nvidia.com/cuda/parallel-thread-execution/index.html
(mma.884 section, FP32 accumulator).
For example, the matrix L corresponding to blockTileSize=[32,16] is:
warp 0
--------------------------------/\-------------------------------
[ 0 0 2 2 8 8 10 10 0 0 2 2 8 8 10 10 ]
[ 1 1 3 3 9 9 11 11 1 1 3 3 9 9 11 11 ]
[ 0 0 2 2 8 8 10 10 0 0 2 2 8 8 10 10 ]
[ 1 1 3 3 9 9 11 11 1 1 3 3 9 9 11 11 ]
[ 4 4 6 6 12 12 14 14 4 4 6 6 12 12 14 14 ]
[ 5 5 7 7 13 13 15 15 5 5 7 7 13 13 15 15 ]
[ 4 4 6 6 12 12 14 14 4 4 6 6 12 12 14 14 ]
[ 5 5 7 7 13 13 15 15 5 5 7 7 13 13 15 15 ]
[ 16 16 18 18 20 20 22 22 16 16 18 18 20 20 22 22 ]
[ 17 17 19 19 21 21 23 23 17 17 19 19 21 21 23 23 ]
[ 16 16 18 18 20 20 22 22 16 16 18 18 20 20 22 22 ]
[ 17 17 19 19 21 21 23 23 17 17 19 19 21 21 23 23 ]
[ 24 24 26 26 28 28 30 30 24 24 26 26 28 28 30 30 ]
[ 25 25 27 27 29 29 31 31 25 25 27 27 29 29 31 31 ]
[ 24 24 26 26 28 28 30 30 24 24 26 26 28 28 30 30 ]
[ 25 25 27 27 29 29 31 31 25 25 27 27 29 29 31 31 ]
warp 1 = warp0 + 32
--------------------------------/\-------------------------------
[ 32 32 34 34 40 40 42 42 32 32 34 34 40 40 42 42 ]
[ 33 33 35 35 41 41 43 43 33 33 35 35 41 41 43 43 ]
[ ............................................................... ]
// -------------------------------- version = 2 --------------------------- //
For second-gen tensor cores, the implicit warpTileSize is [16, 8].
Information about this layout can be found in the official PTX documentation
https://docs.nvidia.com/cuda/parallel-thread-execution/index.html
(mma.16816 section, FP32 accumulator).
For example, the matrix L corresponding to blockTileSize=[32,16] is:
warp 0 warp 1
-----------------/\------------- ----------------/\-------------
[ 0 0 1 1 2 2 3 3 32 32 33 33 34 34 35 35
[ 4 4 5 5 6 6 7 7 36 36 37 37 38 38 39 39
[ .............................. ..............................
[ 28 28 29 29 30 30 31 31 60 60 61 61 62 62 63 63
[ 0 0 1 1 2 2 3 3 32 32 33 33 34 34 35 35
[ 4 4 5 5 6 6 7 7 36 36 37 37 38 38 39 39
[ .............................. ..............................
[ 28 28 29 29 30 30 31 31 60 60 61 61 62 62 63 63
warp 3 warp 4
----------------/\------------- ----------------/\-------------
[ 64 64 65 65 66 66 67 67 96 96 97 97 98 98 99 99
[ 68 68 69 69 70 70 71 71 100 100 101 101 102 102 103 103
[ .............................. ...............................
[ 92 92 93 93 94 94 95 95 124 124 125 125 126 126 127 127
[ 64 64 65 65 66 66 67 67 96 96 97 97 98 98 99 99
[ 68 68 69 69 70 70 71 71 100 100 101 101 102 102 103 103
[ .............................. ...............................
[ 92 92 93 93 94 94 95 95 124 124 125 125 126 126 127 127
}];
let parameters = (
ins
"unsigned":$version,
ArrayRefParameter<"unsigned">:$warpsPerCTA
);
let extraClassDeclaration = extraBaseClassDeclaration;
}
def SliceEncodingAttr : DistributedEncoding<"SliceEncoding"> {
let mnemonic = "slice";
let description = [{
TODO: improve docs
A = [x x x x x x x x]
parent = [0 1 2 3 ]
[4 5 6 7 ]
[8 9 10 11]
[12 13 14 15]
dim = 0
Then the data of A would be distributed as follow between the 16 CUDA threads:
L(A) = [ {0,4,8,12} , {1,5,9,13} , ... {3,7,11,15}, {0,4,8,12} , ..., {3,7,11,15} ]
This is useful for constructing the inverse layout of an expand_dims operation during some optimization passes.
}];
let parameters = (
ins
"unsigned":$dim,
// TODO: constraint here to only take distributed encodings
"Attribute":$parent
);
let extraClassDeclaration = extraBaseClassDeclaration # [{
template<class T>
SmallVector<T> paddedShape(ArrayRef<T> shape) const;
}];
}
def DotOperandEncodingAttr : DistributedEncoding<"DotOperandEncoding"> {
let mnemonic = "dot_op";
let description = [{
In TritonGPU dialect, considering `d = tt.dot a, b, c`
tt.dot's operands a and b must be of DotOperandEncodingAttr layout.
a's opIdx is 0, b's opIdx is 1.
The parend field in DotOperandEncodingAttr is the layout of d.
For MMA v1, an additional attribute `isMMAv1Row` determines whether e.g. the a operand is used
in the context of an mma.884.row.col or an mma.884.col.col operation. See the PTX ISA documentation
section 9.7.13.4.1 for more details.
}];
let parameters = (
ins
"unsigned":$opIdx,
"Attribute":$parent,
"Attribute":$isMMAv1Row
);
let builders = [
AttrBuilder<(ins "unsigned":$opIdx,
"Attribute":$parent), [{
Attribute isMMAv1Row;
if(parent.isa<MmaEncodingAttr>() &&
parent.cast<MmaEncodingAttr>().getVersion() == 1){
isMMAv1Row = BoolAttr::get(context, true);
}
return $_get(context, opIdx, parent, isMMAv1Row);
}]>
];
let extraClassDeclaration = extraBaseClassDeclaration;
}
#endif