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fix: allow mixed turbo/q8_0 KV cache types in CUDA flash-attention selection - #3

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thecodacus merged 2 commits into
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fable5/turbo-fattn-vec-routing
Jul 18, 2026
Merged

thecodacus merged 2 commits into
perffrom
fable5/turbo-fattn-vec-routing

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@thecodacus thecodacus commented Jul 18, 2026

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Problem

With the default build (no GGML_CUDA_FA_ALL_QUANTS), CUDA flash-attention kernel selection rejected any mixed K/V cache type pair. A turbo KV setup is almost always mixed (ctk q8_0 + ctv turbo2/3), so the FA support probe failed, fa auto disabled flash attention, and context creation either refused the quantized V cache outright or fell back to the non-FA path, whose materialized KQ buffer (~8.7 GiB at 128k ctx / ubatch 1024) OOMs before a single token:

W resolve_fused_ops: Flash Attention not supported, set to disabled
E llama_init_from_model: ... quantized V cache was requested, but this requires Flash Attention
E ggml_backend_cuda_buffer_type_alloc_buffer: allocating 8710.00 MiB ... out of memory

-fa on masked the bug (probe skipped), which is why CLI runs passed while every server load failed.

Fix

  • Allow exactly the mixed pairs with compiled FA template instances: turbo2/3/4 against each other, q8_0, and f16. All other mixes stay rejected as before.
  • Gate turbo head-dim geometry (multiples of 64; 128 for turbo4) so shapes without a compiled instance report unsupported instead of asserting at dispatch.
  • llama-bench: accept turbo2/3/4 in -ctk/-ctv (its private type-name table predated the turbo types).

Prefill takes the same dequant-to-F16 MMA path as q8_0, so there is no turbo-specific prefill cost.

Verified — RTX 3060, Qwen3.6-35B-A3B Q4_K_M, -ncmoe 26 -fa 1 -ctk q8_0

ctv pp2048 t/s tg64 t/s
q8_0 527.6 49.1
turbo2 525.8 49.2

Exact previously-failing config (fa auto, ubatch 1024, ctx 128000, ctk q8_0 + ctv turbo2) now loads with FA enabled and generates correctly.

…lection

Without GGML_CUDA_FA_ALL_QUANTS (the default), kernel selection
rejected any K/V type mismatch. A turbo KV setup is almost always
mixed (ctk q8_0 + ctv turbo2/3), so the flash-attention probe failed,
FA was auto-disabled, and context creation either refused the
quantized V cache outright or fell back to the non-FA path whose
KQ buffer (~8.7 GiB at 64k ctx, ubatch 1024) OOMs at load.

Allow exactly the mixed pairs that have FA template instances
compiled in: turbo2/3/4 against each other, q8_0, and f16. Also gate
turbo head-dim geometry (multiples of 64; 128 for turbo4) so shapes
without a compiled instance report unsupported instead of asserting
at dispatch.

Forcing -fa on masked the bug (the probe is skipped); server
deployments use fa auto and hit it on every load.
@thecodacus
thecodacus force-pushed the fable5/turbo-fattn-vec-routing branch from 8e5d80f to c0d11e7 Compare July 18, 2026 22:28
The common arg parser already accepts them for llama-completion and
llama-server; llama-bench has its own name table and rejected -ctk/-ctv
turbo values.
@thecodacus thecodacus changed the title fix: route turbo KV flash-attention to the vector kernel at any batch size fix: allow mixed turbo/q8_0 KV cache types in CUDA flash-attention selection Jul 18, 2026
@thecodacus
thecodacus merged commit 4cd54c6 into perf Jul 18, 2026
12 of 27 checks passed
thecodacus pushed a commit that referenced this pull request Sep 7, 2026
…rg#24908)

* Add preliminary MiniMax-M3 support

Text-only port that re-uses existing components: MiniMax-M2 style GQA with
per-head QK-norm and partial rotary, DeepSeek-V3 style leading-dense and
routed/shared experts, and swigluoai activation. Sparse attention is not
yet supported (dense fallback); vision tower and MTP heads are dropped.

* MiniMax-M3 vision tower (mmproj + clip graph)

* Delete m3_vision_ref.py

* Update clip.cpp

* MSA

* Update constants.py

* Update minimax.py

* Cache creation. Working withotu flash attention

* Added flash attention for sparse layers

* Decomposed slow cpu OP into GPU + CPU ops. Massive speedup over long ctx

* Rewrote indexer op to be cuda native. Modified flash attention to match per group block picking

* Implement sparse attention calc out of stock ops.

* Fix a cache allocation and cont issue

* Fixed -fa auto crash, flagged debug spots

* Delete vocab.json

* Delete model.safetensors.index.json

* Delete generation_config.json

* Delete Minimax directory

* Handled multi stream case to fall back on Dense Attention

* Development scaffolding cleanup. No functional change to the decode or
4-way paths. Full debug harness remains at <8136a9c68ed7a5eb009aa67bba3fda8062f4648f> for reproducing the
selection-parity validation.

* Remove redundant comment from minimax-m3.cpp

* Changed 3 Gelu Ops for vision into Gelu_erf ops

* Assert that n_kv is multiple of 128

* Rename MSA index tensors to indexer convention

Note: All GGUFs generated before this change will need to be regenerated.

* Fix incorrect Assert

* Review driven changes (#3)

* Remove comment from conversion minimax.py

Co-authored-by: Sigbjørn Skjæret <1629204+CISC@users.noreply.github.com>

* Remove whitespaces from constants.py

Co-authored-by: Sigbjørn Skjæret <1629204+CISC@users.noreply.github.com>

* Tighten comment in minimax.py

Co-authored-by: Sigbjørn Skjæret <1629204+CISC@users.noreply.github.com>

* inherit MiniMax-M3 from MiniMax-M2

* drop dead text_config fallbacks

* Add indexer writer methods

* Reuse LLM_FFN_SWIGLU_OAI_MOE

* Remove duplicate  indexer setters, add only block_size/local_blocks, follow value naming convention

* Fix conversion error /gguf_writer.py

Co-authored-by: Sigbjørn Skjæret <1629204+CISC@users.noreply.github.com>

* Update gguf-py/gguf/gguf_writer.py

Co-authored-by: Sigbjørn Skjæret <1629204+CISC@users.noreply.github.com>

* Update gguf-py/gguf/tensor_mapping.py

Co-authored-by: Sigbjørn Skjæret <1629204+CISC@users.noreply.github.com>

* Update conversion/minimax.py

Co-authored-by: Sigbjørn Skjæret <1629204+CISC@users.noreply.github.com>

* Update conversion/minimax.py

Co-authored-by: Sigbjørn Skjæret <1629204+CISC@users.noreply.github.com>

* Remove whitespace in src/llama-kv-cache.cpp

Co-authored-by: Sigbjørn Skjæret <1629204+CISC@users.noreply.github.com>

* Remove Whitespace in Update src/llama-model.h

Co-authored-by: Sigbjørn Skjæret <1629204+CISC@users.noreply.github.com>

* Remove whitespace in src/llama-hparams.h

Co-authored-by: Sigbjørn Skjæret <1629204+CISC@users.noreply.github.com>

* remove multimodal code upon maintainer request. Will be made as a separate PR

* Whitespace clean in tensor_mapping.py

* Log cache size on launch, block ctx shift, support prompt caching

Log indexer cache size on launch

Disallow ctx shift

Support prompt caching

* Update minimax-m3.cpp

* Optimize implementation, add multi stream support. 

Fully rewrote minimax-m3.cpp for speed and buffer size gains:

Unified the 4-way + decode, 1 FA call per layer instead of 4, with the groups mapped onto ne[3]

Custom CPU op now emits block-level mask, expanded on GPU, which causes CPU to GPU transfer to shrinks at prefill

Decode: ~25 nodes/layer vs ~50, no per-group concats/conts

Unified selection semantics, so both regimes rank bs + local bias (position-anchored local force), which means prefill/decode can no longer disagree on selection

can_reuse on the MSA bias input. Graph reuse at decode restored (was rebuilding the full graph every token)

In-place mask adds, shrinking compute buffer ~6.8 to ~4.2 GiB at ub2048/62k

Multi-stream: MSA now runs with -np N when kv_unified=false. Decode stays batched across streams (still 1 FA call), prefill loops per stream. dense fallback only for --kv-unified + multi-seq

Measured effect on expert offload bound setup: decode 6.2(4WAY)–7.15(MSA_decode) -> 7.7~7.8 t/s, flat from 5k to 60k+. prefill around 10% faster. buffer about 20% smaller, multi-user support.

* set default cache type to F32

* Fix potential DSA double indexer cache  allocation bug, only allocate in-cache k_idx for archs that opt in

* remove F16 downcasts in MSA attention, force F32 indexer score accum

* Add Minimax eos to llama vocab

* Guard edge case where idx cache can become stale after a tail trim

* Update llama-kv-cache.h

* Update llama-kv-cache.cpp

* Update llama-kv-cache.cpp

* Update llama-kv-cache.h

* Update llama-kv-cache.cpp

* Review driven changes

* style fix

* indexer hparams are required

* fix tests

* fix lint

---------

Co-authored-by: Daniel Han <danielhanchen@gmail.com>
Co-authored-by: Sigbjørn Skjæret <1629204+CISC@users.noreply.github.com>
Co-authored-by: Xuan Son Nguyen <son@huggingface.co>
thecodacus pushed a commit that referenced this pull request Sep 7, 2026
* Add preliminary MiniMax-M3 support

Text-only port that re-uses existing components: MiniMax-M2 style GQA with
per-head QK-norm and partial rotary, DeepSeek-V3 style leading-dense and
routed/shared experts, and swigluoai activation. Sparse attention is not
yet supported (dense fallback); vision tower and MTP heads are dropped.

* MiniMax-M3 vision tower (mmproj + clip graph)

* Delete m3_vision_ref.py

* Update clip.cpp

* MSA

* Update constants.py

* Update minimax.py

* Cache creation. Working withotu flash attention

* Added flash attention for sparse layers

* Decomposed slow cpu OP into GPU + CPU ops. Massive speedup over long ctx

* Rewrote indexer op to be cuda native. Modified flash attention to match per group block picking

* Implement sparse attention calc out of stock ops.

* Fix a cache allocation and cont issue

* Fixed -fa auto crash, flagged debug spots

* Delete vocab.json

* Delete model.safetensors.index.json

* Delete generation_config.json

* Delete Minimax directory

* Handled multi stream case to fall back on Dense Attention

* Development scaffolding cleanup. No functional change to the decode or
4-way paths. Full debug harness remains at <8136a9c68ed7a5eb009aa67bba3fda8062f4648f> for reproducing the
selection-parity validation.

* Remove redundant comment from minimax-m3.cpp

* Changed 3 Gelu Ops for vision into Gelu_erf ops

* Assert that n_kv is multiple of 128

* Rename MSA index tensors to indexer convention

Note: All GGUFs generated before this change will need to be regenerated.

* Fix incorrect Assert

* Review driven changes (#3)

* Remove comment from conversion minimax.py

Co-authored-by: Sigbjørn Skjæret <1629204+CISC@users.noreply.github.com>

* Remove whitespaces from constants.py

Co-authored-by: Sigbjørn Skjæret <1629204+CISC@users.noreply.github.com>

* Tighten comment in minimax.py

Co-authored-by: Sigbjørn Skjæret <1629204+CISC@users.noreply.github.com>

* inherit MiniMax-M3 from MiniMax-M2

* drop dead text_config fallbacks

* Add indexer writer methods

* Reuse LLM_FFN_SWIGLU_OAI_MOE

* Remove duplicate  indexer setters, add only block_size/local_blocks, follow value naming convention

* Fix conversion error /gguf_writer.py

Co-authored-by: Sigbjørn Skjæret <1629204+CISC@users.noreply.github.com>

* Update gguf-py/gguf/gguf_writer.py

Co-authored-by: Sigbjørn Skjæret <1629204+CISC@users.noreply.github.com>

* Update gguf-py/gguf/tensor_mapping.py

Co-authored-by: Sigbjørn Skjæret <1629204+CISC@users.noreply.github.com>

* Update conversion/minimax.py

Co-authored-by: Sigbjørn Skjæret <1629204+CISC@users.noreply.github.com>

* Update conversion/minimax.py

Co-authored-by: Sigbjørn Skjæret <1629204+CISC@users.noreply.github.com>

* Remove whitespace in src/llama-kv-cache.cpp

Co-authored-by: Sigbjørn Skjæret <1629204+CISC@users.noreply.github.com>

* Remove Whitespace in Update src/llama-model.h

Co-authored-by: Sigbjørn Skjæret <1629204+CISC@users.noreply.github.com>

* Remove whitespace in src/llama-hparams.h

Co-authored-by: Sigbjørn Skjæret <1629204+CISC@users.noreply.github.com>

* Update minimax_m3.cpp

Rewrite code comment based on feedback and to better reflect the actual architecture, and reuse existing build_vit

* Rename minimax_m3.cpp to minimax-m3.cpp

* Update CMakeLists.txt

* Remove debug code from clip.cpp

* Update clip.cpp

* Update comments in tools/mtmd/models/minimax-m3.cpp

* Permute Q/K at conversion, drop precomputed sin/cos

* Log cache size on launch, block ctx shift, support prompt caching

Log indexer cache size on launch

Disallow ctx shift

Support prompt caching

* Update minimax-m3.cpp

* Optimize implementation, add multi stream support. 

Fully rewrote minimax-m3.cpp for speed and buffer size gains:

Unified the 4-way + decode, 1 FA call per layer instead of 4, with the groups mapped onto ne[3]

Custom CPU op now emits block-level mask, expanded on GPU, which causes CPU to GPU transfer to shrinks at prefill

Decode: ~25 nodes/layer vs ~50, no per-group concats/conts

Unified selection semantics, so both regimes rank bs + local bias (position-anchored local force), which means prefill/decode can no longer disagree on selection

can_reuse on the MSA bias input. Graph reuse at decode restored (was rebuilding the full graph every token)

In-place mask adds, shrinking compute buffer ~6.8 to ~4.2 GiB at ub2048/62k

Multi-stream: MSA now runs with -np N when kv_unified=false. Decode stays batched across streams (still 1 FA call), prefill loops per stream. dense fallback only for --kv-unified + multi-seq

Measured effect on expert offload bound setup: decode 6.2(4WAY)–7.15(MSA_decode) -> 7.7~7.8 t/s, flat from 5k to 60k+. prefill around 10% faster. buffer about 20% smaller, multi-user support.

* set default cache type to F32

* Fix potential DSA double indexer cache  allocation bug, only allocate in-cache k_idx for archs that opt in

* remove F16 downcasts in MSA attention, force F32 indexer score accum

* Add Minimax eos to llama vocab

* Guard edge case where idx cache can become stale after a tail trim

* Update llama-kv-cache.h

* Update llama-kv-cache.cpp

* Update llama-kv-cache.cpp

* Update llama-kv-cache.h

* Change resize Pad to none, resize alg to Bicubic Pillow

* Review driven changes

* Update llama-kv-cache.cpp

* rm unrotated pos_t

* fused rope w + pad

* rename merge --> merger for consistency

* add review skill for mtmd

* graph should use hparams n_merge

* fix lint

---------

Co-authored-by: Daniel Han <danielhanchen@gmail.com>
Co-authored-by: Sigbjørn Skjæret <1629204+CISC@users.noreply.github.com>
Co-authored-by: Xuan Son Nguyen <son@huggingface.co>
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