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composable_kernel/include/ck_tile
Ville Pietilä 60b276647b [rocm-libraries] ROCm/rocm-libraries#8157 (commit b0d9d39)
[CK Tile] Rule-based configuration generation in CK
 Dispatcher codegen (#8157)
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## Motivation

The CK Tile Dispatcher code generation for CK Tile Profiler relies on
flat JSON files to list the generated configurations. This approach has
the following problems

- The JSON files are verbose
- The JSON files get easily out of sync with the CK Builder .config
files from which they were generated from.
- The JSON file based configuration make it hard to list explicitly the
rules that govern the instance generation.

## Technical Details

Replaced the JSON files with a rule based configuration. To preserve the
existing functionality, the `profiler` and the `tests` instance sets are
generated directly from the CK Builder config files. The JSON config
files are removed from source control, and the "on-the-fly" generation
guarantees that the Dispatcher codegen uses up to date configurations.

This is PR introduces six different rule sets for the CK Tile Dispatcher
code generation

1. `profiler`: matches with the old JSON set of profiler configurations.
2. `tests`: matches with the old JSON set of tests configurations.
3. `full`: full configuration set created from a rule-based config
selection
4. `full-tests`: a subset of `full` for generating configurations for
convolution integration tests.
5. `tiny`: a subset of `full-tests` to produce the minimal set of
configurations to test the Dispatcher codegen.
6. `default`: the default rules, which corresponds to the existing
heuristic rules for configuration selection. This ensures that ML based
kernel selection doesn't get broken.

The main use of the `full` rule set is to define a reasonable solution
space for the possible implicit GEMM configurations. We start from the
configurations that allowed by the device architecture. The `full` rule
set defines the relevant tile sizes for each convolution direction. From
the tile size we have a curated mapping to the number of waves over the
different GEMM axes, i.e., we describe how many waves each GEMM
dimensions corresponds to. The GEMM-K wave tile dimension can be
computed from the other parameters and does not need to be listed
explicitly.

An orthogonal axis to the tiling strategy is the vectorization strategy.
This mainly defined by the data type and hardware as in general, we want
to use the maximum possible load widths. The maximum sizes for each
convolution direction variant are defined by the implicit GEMM matrix
dimensions. For cases where have a low number of channels per
convolution group, we need smaller vector load sizes. These are captured
by the `VecStrategy` enumeration in the codegen rules.

The problem with the rule based configuration selection is that we "over
generate" configurations. The old JSON configurations compose
approximately 25% of all configuration that the `full` rule set creates.
The additional configurations are valid, but they many not provide any
performance benefits. Hence, we keep the `profiler` and `tests` rule set
for now to avoid building an excessive amount configurations by default.
The `full` rule set can be taken into use by specifying CMake
configuration flag `-D DISPATCHER_RULE_SET=full`. By default, the
`tests` rule set is used, i.e., we don't change the existing bahaviour.

## Test Plan

Added a new stage in the CI/CD pipeline that ensures the Dispatcher
codegen rules are up to date. Otherwise the functionality is covered by
the existing CI/CD tests. There are no functional changes to the
convolution kernels. Only how the different instances are generated.

## Test Result

If the CK Tile conv instances build without errors, the Dispatcher
codegen is generating valid code. If all tests in CI/CD pipeline are
passing, the Dispatcher codegen generates valid instances.

## Submission Checklist

- [x] Look over the contributing guidelines at
https://github.com/ROCm/ROCm/blob/develop/CONTRIBUTING.md#pull-requests.
2026-06-18 01:22:50 +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.