Christopher Millette
a170e2bd9d
[rocm-libraries] ROCm/rocm-libraries#5939 (commit 6fb1791)
...
[CK_TILE] Flatten nested static_for loops into static_ford
(#5939 )
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
## Summary
Mechanical conversion of 129 nested `static_for`/`static_ford` patterns
to flat `static_ford` across 29 ck_tile header files.
Each conversion eliminates intermediate lambda closure instantiations by
replacing nested compile-time loops with a single flat iteration using
index decomposition.
### What `static_ford` eliminates
When `static_for` loops are nested, each level creates unique closure
types:
```cpp
// BEFORE: M + M×N = 20 IR functions (for M=4, N=4)
static_for<0, 4, 1>{}([&](auto m) { // 4 closure instantiations
static_for<0, 4, 1>{}([&](auto n) { // 4×4 = 16 closure instantiations
body(m, n);
});
});
// AFTER: M×N = 16 IR functions (with ford_applier, no intermediates)
static_ford<sequence<4, 4>>{}([&](auto mn) {
constexpr auto m = number<mn[number<0>{}]>{};
constexpr auto n = number<mn[number<1>{}]>{};
body(m, n);
});
```
### Pattern categories converted
| Category | Count | Description |
|----------|-------|-------------|
| C (2-level `static_for` chains) | 112 | Nested `static_for` →
`static_ford` |
| C3 (3-level `static_for` chains) | 9 | Three consecutive nests →
`static_ford` |
| Partial rescue | 3 | Outer 2 levels of blocked 4-level nests |
| B (nested `static_ford` merge) | 5 | Two nested `static_ford` → single
higher-dim `static_ford` |
| **Total** | **129** | Across 29 files |
6 false positives were detected and reverted (in `tensor_adaptor.hpp`,
`tile_distribution.hpp`, `tile_distribution_encoding.hpp`) where the
inner loop bound depended on the outer variable.
### Files changed by family
| Family | Files | Sites |
|--------|-------|-------|
| Block GEMM | 12 | ~20 |
| FlatMM pipelines | 4 | ~69 (including 5 ford-ford merges) |
| GEMM quant | 7 | ~22 |
| FlatMM kernel | 1 | 2 |
| FMHA | 1 | 2 |
| Reduce/norm | 2 | 2 |
| Epilogue | 1 | 1 |
### Blocked locations from review comments
- **block_gemm_areg_breg_creg_v1.hpp:356** — BLOCKED: runtime scale
loads (`scale_a_slice`, `scale_b_slice`, A warp tensor load) between
every nesting level
- **block_universal_gemm_ar_aquant_flatbr_bquant_cr.hpp:228** — BLOCKED:
`zero_accumulators()` before inner loop; `sched_barrier` + conditional
`block_sync_lds()` after inner loop
- **block_universal_gemm_as_aquant_bs_bquant_cr.hpp:298** — BLOCKED:
runtime `CWarpTensor` construction before inner loop; quantization scale
application code after inner loop
- **block_universal_gemm_as_aquant_bs_cr.hpp:277** — BLOCKED: same
pattern as above
- **block_universal_gemm_as_bs_bquant_cr.hpp:367** — BLOCKED: same
pattern as above
## Depends on
- #5938 ([CK_TILE] Optimize static_ford and sequence compile-time
infrastructure) — provides the `ford_applier` that makes these
conversions beneficial. Without it, `static_ford` uses a recursive
implementation that provides no IR function savings.
## Results (combined with #5938 )
### Build Time (Wilcoxon signed-rank, 7 paired trials, gfx942)
| Target | Base (s) | Treat (s) | Delta | % | Significant? |
|--------|----------|-----------|-------|---|-------------|
| **flatmm** | 161.1 | 149.0 | **-12.1s** | **-7.5%** | **YES** (p<0.01,
7/7 wins) |
| **universal_gemm** | 225.4 | 220.3 | **-5.1s** | **-2.3%** | **YES**
(p<0.01, 7/7 wins) |
### IR Function Counts (device trace, gfx942)
| Target | InstFunc | CodeGen |
|--------|----------|---------|
| universal_gemm | **-8.5%** | **-9.2%** |
| flatmm | **-7.6%** | **-10.5%** |
### ASM Equivalence
5/5 PASS — 650,151 lines verified identical (gfx942). TUs:
universal_gemm, flatmm_basic, fmha_bwd, reduce, bscale.
## Test plan
- [x] ASM equivalence verified (650K lines, gfx942)
- [x] Wilcoxon timing verified (7 trials, p<0.01)
- [x] IR function counts verified (-7.6% to -10.5% CodeGen reduction)
- [ ] CI
🤖 Generated with [Claude Code](https://claude.com/claude-code )
2026-04-07 14:38:07 +00:00
feli
4bc610416a
Ck tile/layernorm: implement naive reduce, opt performance ( #1784 )
...
* add no welford
* enable output raw
* raw of int8
* fix build
* fix smoke test err
* [ck_tile]layernorm: fix welford ok, set int8 and bf16 small N as default and others open by generate
* [cktile]layernorm, fix err commit files and remove uselss
* fix quant 8192 err & change norm_reduce class and file name
---------
Co-authored-by: coderfeli <coderfeli@163.com >
Co-authored-by: carlushuang <carlus.huang@amd.com >
2025-01-03 14:28:59 +08:00
