feat(pa): add persistent FP8 decode path - #454
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April 2, 2026 08:13
Add the persistent-scheduling FP8 paged-attention kernel and a PS-focused regression harness so split-reduce behavior can be exercised against the Gluon reference. Signed-off-by: sixifang <sixifang@amd.com> Made-with: Cursor
Signed-off-by: sixifang <sixifang@amd.com> Made-with: Cursor
Signed-off-by: sixifang <sixifang@amd.com> Made-with: Cursor
Signed-off-by: sixifang <sixifang@amd.com> Made-with: Cursor
Signed-off-by: sixifang <sixifang@amd.com> Made-with: Cursor
Signed-off-by: sixifang <sixifang@amd.com> Made-with: Cursor
Signed-off-by: sixifang <sixifang@amd.com> Made-with: Cursor
Signed-off-by: sixifang <sixifang@amd.com> Made-with: Cursor
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Pull request overview
Adds a persistent-scheduling (PS) FP8 paged-attention decode implementation (1024-token KV pages / 256-token tiles) and extends the supporting Python/FlyDSL plumbing needed to launch and validate it.
Changes:
- Introduces a new PS-mode PA decode kernel path (plus sliding-window path + reduce integration) in
kernels/pa_decode_fp8.py. - Extends FlyDSL buffer resource descriptor creation to support base-pointer byte offsets for descriptor “windowing”.
- Updates JIT cache keying to include debug-info emission mode, and adds a ROCDL scheduler mask constant used by the new kernels.
Reviewed changes
Copilot reviewed 4 out of 5 changed files in this pull request and generated 7 comments.
Show a summary per file
| File | Description |
|---|---|
| tests/kernels/test_pa.py | Replaced prior PA test with a PS-only regression harness and expanded accuracy/perf checks vs Torch/Gluon. |
| python/flydsl/expr/rocdl/init.py | Adds mask_compute scheduler mask constant. |
| python/flydsl/expr/buffer_ops.py | Adds base_byte_offset support when building buffer resource descriptors. |
| python/flydsl/compiler/jit_function.py | Makes FlyDSL toolchain fingerprint depend on debug-info mode to avoid cache collisions. |
| kernels/pa_decode_fp8.py | Implements persistent-scheduling FP8 PA decode, metadata expansion for block-split partials, and sliding-window support. |
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added 6 commits
April 29, 2026 05:43
Signed-off-by: sixifang <sixifang@amd.com> Made-with: Cursor
Signed-off-by: sixifang <sixifang@amd.com> Made-with: Cursor
Signed-off-by: sixifang <sixifang@amd.com> Made-with: Cursor
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April 30, 2026 04:00
Signed-off-by: sixifang <sixifang@amd.com> Made-with: Cursor
Signed-off-by: sixifang <sixifang@amd.com> Made-with: Cursor
Signed-off-by: sixifang <sixifang@amd.com> Made-with: Cursor
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Please merge the PR, it's a functional implementation, syntax update could be done in the next PR. |
Move PA descriptor windowing into the kernel helper so the compiler buffer API stays unchanged while preserving the generated ISA. Co-authored-by: Cursor <cursoragent@cursor.com>
Keep PA descriptor windowing on the buffer resource helper and fold the LDS buffer-load convenience wrapper into raw_ptr_buffer_load_lds defaults. Co-authored-by: Cursor <cursoragent@cursor.com>
Remove the unused LDS load convenience wrapper without adding defaults to the raw ROCDL wrapper. Co-authored-by: Cursor <cursoragent@cursor.com>
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May 8, 2026
* feat(pa): add persistent-scheduling FP8 decode path Add the persistent-scheduling FP8 paged-attention kernel and a PS-focused regression harness so split-reduce behavior can be exercised against the Gluon reference. Signed-off-by: sixifang <sixifang@amd.com> Made-with: Cursor --------- Signed-off-by: sixifang <sixifang@amd.com> Co-authored-by: sixifang <sixifang@amd.com> Co-authored-by: felix <felix.li@amd.com> Co-authored-by: Cursor <cursoragent@cursor.com>
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Summary
Test plan
aiterandtritonin the PA test/kernel files when those packages are not installed in the editor environment.Made with Cursor