Files
composable_kernel/test/ck_tile
Christopher Millette 4947624915 [CK_TILE] Optimize ck_tile::sequence to reduce template instantiation depth [2A] (#5028)
## Summary

### Rationale
`ck_tile::sequence` is the most fundamental metaprogramming type in
ck_tile — it underpins
tensor dimensions, strides, loop bounds, and index calculations. Six of
its metafunctions
use recursive template instantiation, producing O(N) to O(N²)
intermediate types that
the compiler must process. When these are used inside deeply nested GEMM
pipelines with
large dimension counts, the cumulative instantiation overhead becomes a
significant
contributor to frontend compile time.

Measurements on `test_gemm_pipeline_compv6` show 84,288
`InstantiateFunction` calls in
the frontend alone. Reducing template instantiation depth in these core
utilities has a
multiplicative effect because they are called from hundreds of sites.

### What changed

| Metafunction | Before | After |
|---|---|---|
| `sequence::modify` | O(N) recursive split/merge | O(1) pack expansion
|
| `sequence_gen` | O(log N) recursive binary split | O(1) via
`__make_integer_seq` |
| `uniform_sequence_gen` | Delegates to `sequence_gen` | O(1) via
`__make_integer_seq` |
| `sequence_reverse_inclusive_scan` | O(N) recursive | O(1) constexpr
for-loop + pack expansion |
| `sequence_inclusive_scan` | Computed via reverse + flip | O(1)
constexpr for-loop (unified impl) |
| `sequence_exclusive_scan` | O(N) recursive merge chain | O(1)
constexpr for-loop + pack expansion |
| `sequence_map_inverse` | O(N²) recursive modify calls | O(1) constexpr
for-loop + pack expansion |

Supporting changes:
- Portable `__type_pack_element` fallback with `__has_builtin` guard
(hipRTC-safe, no `<tuple>` dependency)
- Renamed reserved `__integer_sequence` to `integer_sequence_wrapper`
- Adopted `static_array` from develop (PR #4355) for constexpr
computation
- Unified forward and reverse inclusive scan into a single
`sequence_inclusive_scan_impl` with `bool Reverse` template parameter
- Added `sequence_inclusive_scan` struct (new public API for forward
scan direction)
- Replaced recursive `sequence_exclusive_scan` (3 template
specializations) with `sequence_exclusive_scan_impl` using the same
constexpr for-loop pattern as inclusive scan
- Rewired `exclusive_scan_sequence` and `prefix_sum_sequence` to use new
impl
- Added `CK_TILE_HOST_DEVICE` to `exclusive_scan_sequence` and
`prefix_sum_sequence` to match sibling scan function annotations

### Technical debt and housekeeping
- Unified all `namespace impl` to `namespace detail` across sequence.hpp
for consistency
- Removed dead comment block (orphaned `integer_sequence` alternative)
- Added defensive `static_assert(sizeof...(Is) > 0)` in
`sequence_map_inverse::build_inverse`
- Converted all multi-line Doxygen blocks from `///` to `/** */` per
style guide
- Corrected `constexpr static` to `static constexpr` keyword ordering in
`static_array`
- Added blank line between `#pragma once` and first `#include` in
`static_array.hpp`
- Trimmed redundant 4-line comment on `sequence_gen_helper` to a
one-liner
- Moved `sequence_gen` Doxygen comment below `namespace detail` block so
it directly precedes the struct it documents
- Added Doxygen `@brief`/`@tparam`/`@pre` documentation for
`sequence_gen` and `sequence_map_inverse` public APIs
- Added `@brief` documentation to `static_array` explaining relationship
to `ck_tile::array`
- Added scope comment at `namespace detail` openings

**Note:** `private:`/`public:` access modifier indentation is enforced
at 4 spaces by
`.clang-format`. The style guide calls for left-alignment, but the
formatter overrides
this. Requires a `.clang-format` config change to resolve — not
addressable in code.

### `static_array` hardening (from develop's PR #4355)
- Added zero-length array guard (`T elems[N > 0 ? N : 1]`)
- Added `CK_TILE_HOST_DEVICE` annotations to `operator[]` and `size()`
- Added `#include "ck_tile/core/config.hpp"` (IWYU for
`CK_TILE_HOST_DEVICE`)

### Value
Combined with the `static_ford` changes, measured impact on
`test_gemm_pipeline_compv6`:
- **Frontend: -28.9%** (InstantiateFunction: 84,288 → 69,439)
- **Backend: -13.1%** (CodeGen Functions: 3,170 → 2,203)
- **Wall-clock: -16.3%** (611.6s → 512.2s)

### Files changed (4)
- `sequence.hpp`: Metafunction optimizations, namespace unification,
documentation, style fixes
- `static_array.hpp`: Zero-length guard, `CK_TILE_HOST_DEVICE`,
documentation, style fixes
- `test_sequence.cpp`: 50 unit tests with runtime `EXPECT_EQ` assertions
(new file)
- `CMakeLists.txt`: Register new test target

## Test plan
- [x] 50 runtime unit tests covering all optimized and pre-existing
sequence APIs
- [x] Edge cases: empty sequences, single-element, larger sizes (N=8),
negative values, non-trivial init values
- [x] Both functor signatures tested (`operator()(index_t)` and
`operator()(number<I>)`)
- [x] Both scan reducers (`plus`, `multiplies`) with forward, reverse,
inclusive, and exclusive directions
- [x] Exclusive scan: sum, product, single, empty, non-zero init
- [x] Prefix sum: N+1 output verification, single, empty
- [x] Permutation round-trip verification for `sequence_map_inverse`
- [x] Full sequence public API coverage: modify, gen, uniform_gen, scans
(inclusive, exclusive, prefix sum), map_inverse, make_index_sequence,
size/sum/product, push/pop, reverse, extract, merge, arithmetic
operators, equality, transform
- [x] Portable `__type_pack_element` fallback tested implicitly (same
`at_index_t` interface)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

## Submission Checklist

- [ ] Look over the contributing guidelines at
https://github.com/ROCm/ROCm/blob/develop/CONTRIBUTING.md#pull-requests.

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
Co-authored-by: Max Podkorytov <4273004+tenpercent@users.noreply.github.com>
2026-03-11 14:24:54 -06:00
..
2026-02-02 16:04:40 +08:00

CK Tile Testing Guide

This document describes the test organization and available test targets for CK Tile operations.

Overview

CK Tile tests are organized with multiple levels of granularity to support different development workflows:

  1. Global test labels - Run tests across all operations
  2. Operation-specific umbrella targets - Run all tests for a specific operation
  3. Individual test executables - Run specific tests

Global Test Labels

These targets run tests across all CK operations (not just CK Tile):

ninja smoke

Run fast smoke tests (tests that complete within ~30 seconds on gfx90a).

ninja smoke

ninja regression

Run slower, more comprehensive regression tests.

ninja regression

ninja check

Run ALL available tests in the entire codebase.

ninja check

Operation-Specific Umbrella Targets

These targets allow you to run all tests for a specific CK Tile operation. This is useful when making changes to a particular operation and wanting to validate all related tests without running the entire test suite.

GEMM Operations

ck_tile_gemm_tests

Run all basic GEMM pipeline tests (memory, compute variants, persistent, etc.)

ninja ck_tile_gemm_tests

Test executables included:

  • test_ck_tile_gemm_pipeline_mem
  • test_ck_tile_gemm_pipeline_compv3
  • test_ck_tile_gemm_pipeline_compv4
  • test_ck_tile_gemm_pipeline_persistent
  • test_ck_tile_gemm_pipeline_compv6
  • test_ck_tile_gemm_pipeline_comp_async (gfx95 only)
  • test_ck_tile_gemm_pipeline_*_wmma variants (gfx11/gfx12 only)

ck_tile_gemm_block_scale_tests

Run all GEMM tests with block-scale quantization (AQuant, BQuant, ABQuant, etc.)

ninja ck_tile_gemm_block_scale_tests

Test executables included: 29 test executables covering:

  • AQuant tests (memory pipelines, base layouts, prefill, preshuffle, transpose)
  • ABQuant tests (base, padding, preshuffle)
  • BQuant tests (1D/2D variants, transpose)
  • BQuant with PreshuffleB (decode/prefill, 1D/2D)
  • BQuant with PreshuffleQuant (decode/prefill, 1D/2D)
  • RowColQuant and TensorQuant tests

ck_tile_gemm_streamk_tests

Run all GEMM StreamK tests (tile partitioner, reduction, smoke, extended)

ninja ck_tile_gemm_streamk_tests

Test executables included:

  • test_ck_tile_streamk_tile_partitioner
  • test_ck_tile_streamk_reduction
  • test_ck_tile_streamk_smoke
  • test_ck_tile_streamk_extended

ck_tile_grouped_gemm_quant_tests

Run all grouped GEMM quantization tests

ninja ck_tile_grouped_gemm_quant_tests

Test executables included:

  • test_ck_tile_grouped_gemm_quant_rowcol
  • test_ck_tile_grouped_gemm_quant_tensor
  • test_ck_tile_grouped_gemm_quant_aquant
  • test_ck_tile_grouped_gemm_quant_bquant
  • test_ck_tile_grouped_gemm_quant_bquant_preshuffleb

Other Operations

ck_tile_fmha_tests

Run all FMHA (Flash Multi-Head Attention) tests

ninja ck_tile_fmha_tests

Test executables included: Forward and backward tests for fp16, bf16, fp8bf16, fp32

ck_tile_reduce_tests

Run all reduce operation tests

ninja ck_tile_reduce_tests

Test executables included:

  • test_ck_tile_reduce2d
  • test_ck_tile_multi_reduce2d_threadwise
  • test_ck_tile_multi_reduce2d_multiblock

Individual Test Executables

You can also build and run individual test executables:

Build a specific test

ninja test_ck_tile_gemm_pipeline_mem

Run a specific test directly

./build/bin/test_ck_tile_gemm_pipeline_mem

Run a specific test through ctest

ctest -R test_ck_tile_gemm_pipeline_mem --output-on-failure