Commit Graph
24 Commits
Author SHA1 Message Date
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 dd9280a664 vulkan: Support asymmetric FA in scalar/mmq/coopmat1 paths (#22589) 2026-05-11 12:49:03 +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 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
Jeff Bolz 3238b1400c vulkan: Fix data race/hang in scalar/cm1 flash attention (#17887) 2025-12-14 09:00:00 +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 0e1f838556 vulkan: Fix FA coopmat1 invalid array indexing (#16365)
When computing sinks, the cm1 shader was looping r from 0 to Br rather than
to rows_per_thread. I must have copied this from the scalar path (where it is
correct), and somehow it wasn't causing failures on current drivers.
2025-10-03 11:52:46 +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 e6d65fb02d vulkan: support arbitrary KV dimension in flash attention (#16160)
The "Clamp" spec constant is already based on whether KV is a multiple of Bc,
so use that to control whether bounds checking is performed. Add bounds checking
to the scalar and coopmat1 paths. Coopmat2 didn't need any changes (the K/V
tensors are already optionally clamped, nothing else needed to be changed).
2025-09-27 22:43:39 +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 de2192794f vulkan: Support mul_mat_id with f32 accumulators (#15337)
* vulkan: Add missing bounds checking to scalar/coopmat1 mul_mat_id

* vulkan: Support mul_mat_id with f32 accumulators, but they are not hooked up

- There's no explicit way to request f32 precision for mul_mat_id, but there
probably should be, and this gets the code in place for that.
- A couple fixes to check_results.
- Remove casts to fp16 in coopmat1 FA shader (found by inspection).
2025-08-16 11:18:31 +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 24e86cae72 vulkan: KHR_coopmat flash attention (#13506)
This shader uses coopmat1 to do the Q*K^T multiply. The P*V multiply is more
difficult for various reasons so I haven't done it. Performance for this
shader is around 2.5x better than for the scalar shader when doing prompt
processing. Some of the benefit may be from other optimizations like staging
through shared memory, or splitting by rows.
2025-05-14 11:55:26 +02:00