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composable_kernel/include/ck_tile
Kiefer van Teutem e8f9bb0c19 [CK_Tile] Refactor amdgcn_mma policy structs (#5272)
## Motivation
The point of this MR is to update the intrinsic layout parameters to
simplify them and make them more clear and flexible. Also, a number of
simple refactors were performed to reduce boilerplate and code
duplication.

## Technical Details
In CK Tile and old CK, the full set of information available in the
intrinsic wrappers, for WMMA and MFMA combined, would be something like:

```
// Basic info
using ADataType = void;
using BDataType = void;
using CDataType = void;

using AVecType = ext_vector_t<ADataType, 0>;
using BVecType = ext_vector_t<BDataType, 0>;
using CVecType = ext_vector_t<CDataType, 0>;

// Fragment sizes
static constexpr index_t kM;
static constexpr index_t kN;
static constexpr index_t kK;

// Layout parameters
static constexpr index_t kAMBlock;
static constexpr index_t kBNBlock;

static constexpr index_t kRepeat;
static constexpr index_t kAMLane;
static constexpr index_t kBNLane;
static constexpr index_t kABK0PerLane;
static constexpr index_t kABKLane;
static constexpr index_t kABK1PerLane;

static constexpr index_t kCMLane;
static constexpr index_t kCNLane;
static constexpr index_t kCM0PerLane;
static constexpr index_t kCM1PerLane;

using kABPs2RHssMajor = sequence<2, 1>;
using kABPs2RHssMinor = sequence<1, 0>;
using kABYs2RHsMajor  = sequence<2, 2>;
using kABYs2RHsMinor  = sequence<0, 2>;

using kCPs2RHssMajor = sequence<1, 2>;
using kCPs2RHssMinor = sequence<1, 0>;
using kCYs2RHsMajor  = sequence<1, 1>;
using kCYs2RHsMinor  = sequence<0, 2>;

using kCTPs2RHssMajor = sequence<2, 1>;
using kCTPs2RHssMinor = sequence<1, 0>;
using kCTYs2RHsMajor  = sequence<2, 2>;
using kCTYs2RHsMinor  = sequence<0, 2>;   
 ```
Note that on top of the intrinsic sizes, we have 12 layout parameters. I have reduced this in the new design to:

```
// Basic info
using ADataType = void;
using BDataType = void;
using CDataType = void;

// Fragment sizes
static constexpr index_t kM;
static constexpr index_t kN;
static constexpr index_t kK;

// Layout parameters
static constexpr index_t kABKPerLane; // K2 * K0, Always the same, even
for diff A / B layouts
static constexpr index_t kAKNumAccess; // K2
static constexpr index_t kARepeat; // Used for RDNA3 repeated inputs and
CDNA block hiding.
static constexpr index_t kBKNumAccess; // K2
static constexpr index_t kBRepeat; // Used for RDNA3 repeated inputs and
CDNA block hiding.
static constexpr index_t kCMPerLane;   // M2 * M0
static constexpr index_t kCMNumAccess; // M2

// Derived properties
using AVecType = ext_vector_t<ADataType, 0>;
using BVecType = ext_vector_t<BDataType, 0>;
using CVecType = ext_vector_t<CDataType, 0>;
```

Note that there are now only 7 layout parameters and no more dimensionality orderings. Believe it or not these 7 parameters are more general than the original 12, and can handle intrinsic and mid-level features that are currently awkward in CK Tile, like dealing with AttrNumAccess, different A / B layouts, more general block-hiding (currently very limited in CK tile), and future arch features.

Furthermore, the A, B and C vec types are now derived directly from the layout parameters to ensure internal consistency.

I added a detailed explanation of the new params in terms of register mappings at the top of amgcn_mma.hpp

Other refactorings I did in this MR:

- Make an amdgcn_mma_base struct to drastically reduce code duplication and potential bugs. Should also make auto-generating the amd_gcn specializations much easier.
- Simplify the MmaOpTraits significantly by only including those parameters that are not directly gettable from the MmaOp itself. This removes duplicated variables and simplifies higher level code.
- Remove overloaded "Block" term for intrinsic dimensions, and replace by "Frag" instead. Some spots were already using the term "Frag" for combined intrinsics, in which case I changed that term to "Chunk" instead.
- Remove some tests that had become somewhat pointless (setting variables and then checking their values immediately).

- [x] Look over the contributing guidelines at https://github.com/ROCm/ROCm/blob/develop/CONTRIBUTING.md#pull-requests.
2026-03-20 09:07:00 -06:00
..
2026-03-20 12:30:08 +00:00
2024-12-12 11:54:03 +08:00

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Composable Kernel Tile

concept

ck_tile provides a programming model with templated abstractions to enable users to implement performance-critical kernels for machine learning workloads. introduces following basic concepts to help users building your own operator

  • tensor coordinate transformation, this is the core concept of layout/index transform abstraction in both compiler time and run time.
  • tile-based programming model, including tile-level api and the concept of distributed tensor.

ck_tile is independently from the old ck, located under /include/ck_tile. You don't need to include anything from old CK, ck_tile has similiar (indeed almost the same) implementations for users to build operators. We will have a transition period to pull everything from old ck into ck_tile, stay tuned.

component

ck_tile is splitted into several componenets including core, host, ops/gemm, ops/fmha... each component you only need to include a single header (e.g #include "ck_tile/core.hpp", #include "ck_tile/ops/fmha.hpp") then you are able to use the function/structure inside (different from old ck)

[core]
ck_tile/core contains all the basic data structure and function to build the kernel, you can only include this header and build your own operators that utilizing all the basic building blocks introduced in ck.

core/container

  • array, store runtime variables with fixed length (tensor index, register buffer, etc...)
  • tuple, same as std::tuple, hold different type of data, and one of the solution to achieve multiple buffer.
  • sequence, compile time integer sequence used to build various internal structures, or to describe tile size
  • other convenient structure build on top of above 3

core/numeric

  • gpu data type like fp16_t, bf16_t, fp8_t... and the conversion between each other
  • constexpr integer similiar to std::integral_constant to be used as compile time integer.
  • math functions and numeric utilities

core/algorithm

  • coordinate transformation system, used to build tensor transform and compile time indexing. This is the core idea introduced in old ck to describe how a tensor is build by several basic transform primitives like merge/unmerge/embed etc... and how we indexing into a ND tensor that finally mapped to 1D memory offset.

core/tensor

  • tensor descriptor, to describe how a ND tensor
  • distributed tensor, describe the storage of this tensor, and the distribution of how a collection of threads collaborately work for this tensor.
  • tile level API, including load_tile, store_tile, shuffle_tile, slice_tile, etc...

[host]
ck_tile/host contains all the host side utilities to launch a kernel, create the device buffer, and some reference implementations. This can be used to create examples (like that under ck_tile example folder) and simple executable to invoke this kernel, so if you only need ck_tile to build your own device library then it's OK to not include this. Based on this, it is recommended to include the specific header you needed under this folder to avoid including unwanted headers (e.g, only include ck_tile/host/kernel_launch.hpp), unless you are writing a host executable.

[ops/gemm, ops/fmha, ops/reduce...]
our implementation of different device operators.

  • warp, warp tile level operator
  • block, block tile level operator
  • pipeline, pipeline that can achieve a customized tile level mainloop (or epilogue). By switching different pipeline to the kernel template you can have different kind of pipeline optimizations.
  • kernel, template interface for users to instantiate a particular kernel

[ops/epilogue]
epilogue part of our kernel. We may extend this epilogue part to let users to build their own cutomized epilogues.

[ref]
reference implementation of cpu or gpu. This folder is supposed to include a specific header on demand.

examples

currently we put all ck_tile related example under /example/ck_tile folder. Please check each example's subfolder.