Commit Graph
37 Commits
Author SHA1 Message Date
Jeff Bolz 8161641005 vulkan: add iq4_nl support back to FA (#24585)
* vulkan: add iq4_nl support back to FA

I was originally concerned about wasting shared memory on the LUT, but it's small
and unlikely to matter in practice.

Also support q1_0 for non-coopmat2.

Fixes #23681

* remove q1_0 FA support
2026-07-28 07:06:03 -05:00
Ruben Ortlam 6e093b80ea vulkan: add Flash Attention support for BFloat16 KV cache (#23420)
* vulkan: add flash attention bf16 kv support

* vulkan: bf16 FA coopmat1 support

* vulkan: bf16 FA coopmat2 support

* fix FA bf16 f32 fallback

* fix FA bf16 coopmat1 shader

* fix FA bf16 coopmat2 shader

* code cleanup

* cleanup comment change

* address feedback

* add O_TYPE for cm2 FA

* use O_TYPE for gqaStore function

* reduce BFLOAT16 ifdefs
2026-05-30 10:39:31 +02:00
Jeff Bolz b36eefc1b3 vulkan: use GL_NV_cooperative_matrix_decode_vector for faster matmul (#23541) 2026-05-27 17:18:28 +02:00
Jeff Bolz dd9280a664 vulkan: Support asymmetric FA in scalar/mmq/coopmat1 paths (#22589) 2026-05-11 12:49:03 +02:00
Jeff Bolz 05e141a6b3 vulkan: Support asymmetric FA in coopmat2 path (#21753)
* vulkan: Support asymmetric FA in coopmat2 path

There has been some recent interest/experimentation with mixed quantization
types for FA. I had originally designed the cm2 FA shader with this in mind
(because I didn't realize it wasn't supported at the time!), this change
adds the missing pieces and enables it.

Also support Q1_0 since people have been trying that out (seems crazy, but
who knows).

We should be able to do similar things in the coopmat1/scalar path, but
there's another change open against the scalar path and I don't want to
conflict.

* reorder cases
2026-05-01 15:28:32 +02:00
Ruben Ortlam aa6f918c1c Vulkan Scalar Flash Attention Refactor (#19625)
* vulkan: allow using fp16 in scalar flash attention shader

* split rows inside of subgroups for faster synchronization

* use row_split when Br >= 4, change reductions to use shared memory if row_split == 1

* use f32 scalar FA if f16 is not supported by device

* fix amd workgroup size issue

* optimize masksh use

* add medium rows FA shader Br size

* fixes

* add padding to mask shmem buffer

* cache q values into registers for KQ

* fuse lf accumulation, pf and v accumulation into a loop

* stage K loads through shmem

* stage V loads through shmem

* only stage through shmem on Nvidia

* default to Bc 32

* also stage V through shmem when this is done for K

* dynamic subgroups for intel

* use vectorized stores

* use float_type for dequantize4 functions

* use smaller scalar rows size for smaller rows count

* relax flash attention split_k condition to allow non-gqa use

* use minimal subgroup size on Intel

* fix shmem support function

* fix rebase issues

* fixes

* Bc 4 for scalar FA is not a valid configuration

* Use wave32 on AMD RDNA for scalar FA

* add Intel shader core count lookup-table

* fix regressions

* device tuning

* tmpsh size fix

* fix editorconfig

* refactor fa tuning logic into a single place

* fix gqa opt logic

* fix block_rows with small n_rows

* amd tuning

* fix hsk=72/80 issue

* tuning

* allow condition skipping for column check

* use float16 for Of if available

* address feedback

* fix bad RDNA performance on head size <= 128 by limiting occupancy

* allow printing pipeline stats

* cleanup and fixes

* limit occupancy for GCN for small batch FA with large HSK

* disable f16 FA for GCN AMD GPUs on the proprietary driver
2026-02-24 08:35:48 +01:00
Jeff Bolz 05a6f0e894 vulkan: restore -inf check in FA shaders (#19582) 2026-02-13 13:35:29 -06:00
Jeff Bolz 1946e46f4c vulkan: For coopmat2 FA, use fp16 accumulators for the final result (#19376)
The cpu and cuda backends use fp16 for the VKQ accumulator type, this change
does the same for vulkan. This helps particularly with large head sizes which
are very register-limited.

I tried this for the coopmat1 path and it slowed down a bit. I didn't try for
scalar.

I applied the softmax bias that the cuda backend uses to avoid overflow,
although I was not able to reproduce the original bug without it.
2026-02-06 09:15:13 +01:00
Jeff Bolz f9bd518a6b vulkan: make FA mask/softcap enables spec constants (#19309)
* vulkan: make FA mask/softcap enables spec constants

* don't specialize for sinks

* bump timeout a little bit
2026-02-06 08:49:58 +01:00
Jeff Bolz 449ec2ab07 vulkan: Preprocess FA mask to detect all-neg-inf and all-zero. (#19281)
Write out a 2-bit code per block and avoid loading the mask when it
matches these two common cases.

Apply this optimization when the mask is relatively large (i.e. prompt
processing).
2026-02-05 09:26:38 -06:00
Ruben Ortlam f6b533d898 Vulkan Flash Attention Coopmat1 Refactor (#19075)
* vulkan: use coopmat for flash attention p*v matrix multiplication

* fix P loading issue

* fix barrier position

* remove reduction that is no longer needed

* move max thread reduction into loop

* remove osh padding

* add bounds checks and padding

* remove unused code

* fix shmem sizes, loop duration and accesses

* don't overwrite Qf, add new shared psh buffer instead

* add missing bounds checks

* use subgroup reductions

* optimize

* move bounds check, reduce barriers

* support other Bc values and other subgroup sizes

* remove D_split

* replace Of register array with shared memory Ofsh array

* parallelize HSV across the rowgroups

* go back to Of in registers, not shmem

* vectorize sfsh

* don't store entire K tile in shmem

* fixes

* load large k tiles to shmem on Nvidia

* adapt shared memory host check function to shader changes

* remove Bc 32 case

* remove unused variable

* fix missing mask reduction tmspsh barrier

* fix mask bounds check

* fix rowmax f16 under/overflow to inf

* fix flash_attn_cm2 BLOCK_SIZE preprocessor directives
2026-01-28 18:52:45 +01:00
Jeff Bolz 33f890e579 vulkan: support flash attention GQA/split_k with small batches (#18938) 2026-01-21 17:43:43 +01:00
Acly 385c3da5e6 vulkan : fix FA mask load with bounds check (coopmat2) (#17606) 2025-11-30 01:03:21 +01:00
Jeff Bolz 234ae7d7bd vulkan: skip all-negative-inf blocks in FA (#17186) 2025-11-15 10:37:25 +01:00
Jeff Bolz fb349848f3 vulkan: Handle FA with all -inf mask values (#16447) 2025-10-20 22:16:08 -05:00
AclyandJeff Bolz e29acf74fe vulkan : incremental shader builds (#16341)
* vulkan (DRAFT): split shader generation by GLSL source file, to improve incremental build times

* support dep-files so shaders are recompiled if their included files change

* rename shader files which are used as "headers" to use .glsl extension
* move glslc extension detection shaders to separate folders
* the above is to prevent them from getting glob'd with the actual compute shaders that need to be compiled

* vulkan : only write embedded shader .hpp/.cpp when they change

* avoid recompiling ggml-vulkan.cpp when editing shaders
* pass single --source argument instead of --input-dir & --filter to shader gen
* check for source file match earlier

* fix hang in vulkan-shaders-gen when there are compilation errors

* early out did not decrement compile_count

* clean up

* fix glslc integer dot product test

* unconditionally write the embedded shader cpp output

* replace output filepath in generated dep-files to match output in CMakeLists

---------

Co-authored-by: Jeff Bolz <jbolz@nvidia.com>
2025-10-04 11:42:56 +02:00
Jeff Bolz e308efda8e vulkan: in flash attention, bounds check against nem1 (don't rely on GGML_KQ_MASK_PAD) (#16316) 2025-10-03 10:33:08 +02:00
Jeff Bolz 94e82c7ead vulkan: clamp matmul and FA results to the max finite value (#15652)
* vulkan: clamp matmul and FA results to the max finite value

* only clamp for fp16
2025-08-31 08:27:57 +02:00
Jeff Bolz c9a24fb932 vulkan: Support FA with any multiple of 8 head sizes (#15537)
The scalar FA shader already handled multiples of 8. The coopmat1 FA
shader assumed 16x16x16 and the shared memory allocations need the HSK
dimensions padded to a multiple of 16. NVIDIA's coopmat2 implementation
requires multiples of 16 for N and K, and needs the matrix dimensions
padded and loads clamped.

Store the FA pipelines in a map, indexed by the pipeline state.
2025-08-24 11:24:25 +02:00
Jeff Bolz c4f53563df vulkan: support fattn sinks (#15126) 2025-08-07 22:44:20 +02:00
Jeff Bolz a0374a67e2 vulkan: Handle updated FA dim2/3 definition (#14518)
* vulkan: Handle updated FA dim2/3 definition

Pack mask boolean and n_head_log2 into a single dword to keep the push
constant block under the 128B limit.

* handle null mask for gqa

* allow gqa with dim3>1
2025-07-05 09:26:04 +02:00
Jeff Bolz 2b72bedec1 vulkan: support mixed/deepseekR1 FA head sizes (#14509)
* vulkan: better parameterize FA by head sizes

* vulkan: support mixed/deepseekR1 FA head sizes
2025-07-03 20:21:14 +02:00
Jeff Bolz 8875523eb3 vulkan: support softmax/FA batch and broadcast (#14449) 2025-07-02 15:48:33 +03:00
Jeff Bolz 2f5a4e1e09 vulkan: move common FA code to flash_attn_base.comp (#13556)
* vulkan: move common FA code to flash_attn_base.comp

* vulkan: move common FA index/stride setup code to flash_attn_base.comp

* build fix
2025-05-17 09:14:55 +02:00
Jeff Bolz 015022bb53 vulkan: enable coopmat2 FA gqa and split_k optimizations more often (#12931)
The grouped query attention optmization doesn't require a power of two ratio,
the only thing relying on it was the modulo operation written as bitwise &.

split_k need not depend on gqa_ratio - enable it any time there's only one
workgroup in the X dimension. The shader gets the split index from the x coord,
and multiple workgroups in the X dimension (pre-split) indicates a larger
FA operation that wouldn't need splitting.
2025-04-16 20:37:25 +02:00
Jeff Bolz a4837577aa vulkan: use aligned loads for flash attention mask (#12853)
Rewrite the stride logic for the mask tensor in the FA shader to force the
stride to be aligned, to allow using more efficient loads.
2025-04-12 10:44:48 +02:00
Jeff Bolz 7ecd780b1a vulkan: Use fp16 for the flash attention P*V multiplication (#12783)
This is consistent with the ggml-cuda behavior and the mul_mat fallback.
2025-04-09 07:12:57 +02:00
Jeff Bolz 0c74b04376 vulkan: fix NaN issue in flash attention shader (#12776)
Use -FLT_MAX/2 rather than -inf as the initial value for computing the maximum.
2025-04-06 11:03:47 +02:00
Jeff Bolz 80b717d493 vulkan: Use unclamped loads for flash attention mask (#12720)
nem1 must be a multiple of GGML_KQ_MASK_PAD, and GGML_KQ_MASK_PAD is a multiple
of the number of rows in the matrix. The KV dim is a multiple of the number of
columns for the aligned shader.
2025-04-06 10:47:13 +02:00
Jeff Bolz f01bd02376 vulkan: Implement split_k for coopmat2 flash attention. (#12627)
When using group query attention, we have one workgroup per KV batch and this
can be very few workgroups (e.g. just 8 in some models). Enable split_k to
spread the work across SMs. This helps a lot when the KV cache is large.
2025-04-02 14:25:08 -05:00
Jeff Bolz be0a0f8cae vulkan: Implement grouped query attention in the coopmat2 FA shader (#12559)
When adjacent batches of Q share the same batches of K/V, batch them into
the same workgroup. For example, when:

dst(128,32,1,1) = FA(q(128,1,32,1), k(128,16640,8,1), v(128,16640,8,1))

previously we would run 32 workgroups computing 1 result each, now we will
run 8 workgroups computing 4 results each.

This doesn't directly translate to better performance (at least when you have
>=32 SMs), but in a subsequent change I'll enable split_k which will scale much
better with 4x fewer workgroups.
2025-04-02 19:40:32 +02:00
Rémy O fc1b0d0936 vulkan: initial support for IQ1_S and IQ1_M quantizations (#11528)
* vulkan: initial support for IQ1_S and IQ1_M quantizations

* vulkan: define MMV kernels for IQ1 quantizations

* devops: increase timeout of Vulkan tests again

* vulkan: simplify ifdef for init_iq_shmem
2025-02-15 09:01:40 +01:00
Rémy O 8a7e3bf17a vulkan: initial support for IQ4_XS quantization (#11501) 2025-02-06 07:09:59 +01:00
Rémy OudomphengandJeff Bolz 66ee4f297c vulkan: implement initial support for IQ2 and IQ3 quantizations (#11360)
* vulkan: initial support for IQ3_S

* vulkan: initial support for IQ3_XXS

* vulkan: initial support for IQ2_XXS

* vulkan: initial support for IQ2_XS

* vulkan: optimize Q3_K by removing branches

* vulkan: implement dequantize variants for coopmat2

* vulkan: initial support for IQ2_S

* vulkan: vertically realign code

* port failing dequant callbacks from mul_mm

* Fix array length mismatches

* vulkan: avoid using workgroup size before it is referenced

* tests: increase timeout for Vulkan llvmpipe backend

---------

Co-authored-by: Jeff Bolz <jbolz@nvidia.com>
2025-01-29 18:29:39 +01:00
Jeff Bolz aea8ddd516 vulkan: fix coopmat2 validation failures (#11284)
mul mat and flash attention shaders were loading f32 types directly into
A/B matrices, which happens to work but is technically invalid usage.
For FA, we can load it as an Accumulator matrix and convert and this
is not in the inner loop and is cheap enough. For mul mat, it's more
efficient to do this conversion in a separate pass and have the input(s)
be f16.

coopmat2 requires SPIR-V 1.6 (related using to LocalSizeId). LocalSizeId
requires maintenance4 be enabled, and SPIR-V 1.6 requires Vulkan 1.3.
2025-01-20 10:38:32 -06:00
Jeff Bolz 44e18ef939 vulkan: fix coopmat2 flash attention for non-contiguous inputs (#11281)
Add code similar to mul_mm_cm2 to force alignment of strides, to avoid
a performance regression.

Add noncontiguous FA tests in test-backend-ops.

Fixes #11268.
2025-01-18 09:26:50 +01:00
Jeff Bolz c9c6e01dae vulkan: Add VK_NV_cooperative_matrix2 support for mul_mat and flash attention (#10206) 2024-12-05 20:15:05 +01:00