CUDA: Add Flash Attention Support for Head Dimension 512 (#20998)

* flash attention support for head dimension 512 added

* FA D=512 - match 576 configs, limit ncols2, revert vec cap

* fix HIP tile kernel build for D=512

* fix HIP tile kernel occupancy for D=512 on AMD

* Apply suggestions from code review

Co-authored-by: Johannes Gäßler <johannesg@5d6.de>

* fix tile FA compilation

---------

Co-authored-by: Johannes Gäßler <johannesg@5d6.de>
This commit is contained in:
Anav Prasad 2026-04-01 07:07:24 +00:00 committed by GitHub
parent 4951250235
commit 88458164c7
No known key found for this signature in database
GPG Key ID: B5690EEEBB952194
14 changed files with 86 additions and 13 deletions

View File

@ -66,6 +66,11 @@ static constexpr __host__ __device__ fattn_mma_config ggml_cuda_fattn_mma_get_co
GGML_CUDA_FATTN_MMA_CONFIG_CASE(256, 256, 32, 128, 2, 32, 128, 128, 128, 2, true);
GGML_CUDA_FATTN_MMA_CONFIG_CASE(256, 256, 64, 128, 2, 32, 128, 128, 128, 2, true);
GGML_CUDA_FATTN_MMA_CONFIG_CASE(512, 512, 8, 64, 4, 32, 256, 256, 128, 1, false);
GGML_CUDA_FATTN_MMA_CONFIG_CASE(512, 512, 16, 64, 4, 32, 256, 256, 128, 1, false);
GGML_CUDA_FATTN_MMA_CONFIG_CASE(512, 512, 32, 128, 2, 32, 128, 128, 128, 1, false);
GGML_CUDA_FATTN_MMA_CONFIG_CASE(512, 512, 64, 256, 1, 32, 128, 128, 128, 1, false);
GGML_CUDA_FATTN_MMA_CONFIG_CASE(576, 512, 8, 64, 4, 32, 288, 256, 128, 1, false);
GGML_CUDA_FATTN_MMA_CONFIG_CASE(576, 512, 16, 64, 4, 32, 288, 256, 128, 1, false);
GGML_CUDA_FATTN_MMA_CONFIG_CASE(576, 512, 32, 128, 2, 32, 160, 128, 128, 1, false);
@ -80,6 +85,11 @@ static constexpr __host__ __device__ fattn_mma_config ggml_cuda_fattn_mma_get_co
GGML_CUDA_FATTN_MMA_CONFIG_CASE(256, 256, 32, 128, 2, 64, 128, 128, 64, 2, true);
GGML_CUDA_FATTN_MMA_CONFIG_CASE(256, 256, 64, 128, 2, 64, 128, 128, 64, 2, true);
GGML_CUDA_FATTN_MMA_CONFIG_CASE(512, 512, 8, 64, 4, 32, 96, 64, 128, 1, false);
GGML_CUDA_FATTN_MMA_CONFIG_CASE(512, 512, 16, 64, 4, 32, 96, 64, 128, 1, false);
GGML_CUDA_FATTN_MMA_CONFIG_CASE(512, 512, 32, 128, 2, 32, 128, 128, 128, 1, false);
GGML_CUDA_FATTN_MMA_CONFIG_CASE(512, 512, 64, 256, 1, 32, 128, 128, 128, 1, false);
GGML_CUDA_FATTN_MMA_CONFIG_CASE(576, 512, 8, 64, 4, 32, 96, 64, 128, 1, false);
GGML_CUDA_FATTN_MMA_CONFIG_CASE(576, 512, 16, 64, 4, 32, 96, 64, 128, 1, false);
GGML_CUDA_FATTN_MMA_CONFIG_CASE(576, 512, 32, 128, 2, 32, 160, 128, 128, 1, false);
@ -89,6 +99,11 @@ static constexpr __host__ __device__ fattn_mma_config ggml_cuda_fattn_mma_get_co
}
static constexpr __host__ __device__ fattn_mma_config ggml_cuda_fattn_mma_get_config_volta(const int DKQ, const int DV, const int ncols) {
GGML_CUDA_FATTN_MMA_CONFIG_CASE(512, 512, 8, 64, 4, 32, 256, 256, 64, 1, false);
GGML_CUDA_FATTN_MMA_CONFIG_CASE(512, 512, 16, 64, 4, 32, 256, 256, 64, 1, false);
GGML_CUDA_FATTN_MMA_CONFIG_CASE(512, 512, 32, 128, 2, 32, 128, 128, 64, 1, false);
GGML_CUDA_FATTN_MMA_CONFIG_CASE(512, 512, 64, 256, 1, 32, 128, 128, 64, 1, false);
GGML_CUDA_FATTN_MMA_CONFIG_CASE(576, 512, 8, 64, 4, 32, 288, 256, 64, 1, false);
GGML_CUDA_FATTN_MMA_CONFIG_CASE(576, 512, 16, 64, 4, 32, 288, 256, 64, 1, false);
GGML_CUDA_FATTN_MMA_CONFIG_CASE(576, 512, 32, 128, 2, 32, 160, 128, 64, 1, false);
@ -103,6 +118,10 @@ static constexpr __host__ __device__ fattn_mma_config ggml_cuda_fattn_mma_get_co
GGML_CUDA_FATTN_MMA_CONFIG_CASE(256, 256, 32, 128, 2, 64, 128, 128, 64, 2, true);
GGML_CUDA_FATTN_MMA_CONFIG_CASE(256, 256, 64, 128, 2, 64, 128, 128, 64, 2, true);
GGML_CUDA_FATTN_MMA_CONFIG_CASE(512, 512, 16, 64, 4, 32, 128, 128, 128, 1, false);
GGML_CUDA_FATTN_MMA_CONFIG_CASE(512, 512, 32, 128, 2, 32, 128, 128, 128, 1, false);
GGML_CUDA_FATTN_MMA_CONFIG_CASE(512, 512, 64, 256, 1, 32, 128, 128, 128, 1, false);
GGML_CUDA_FATTN_MMA_CONFIG_CASE(576, 512, 16, 64, 4, 32, 96, 64, 128, 1, false);
GGML_CUDA_FATTN_MMA_CONFIG_CASE(576, 512, 32, 128, 2, 32, 160, 128, 128, 1, false);
GGML_CUDA_FATTN_MMA_CONFIG_CASE(576, 512, 64, 256, 1, 32, 160, 128, 128, 1, false);
@ -1552,7 +1571,7 @@ static __global__ void flash_attn_ext_f16(
#if defined(FLASH_ATTN_AVAILABLE) && (defined(VOLTA_MMA_AVAILABLE) || defined(TURING_MMA_AVAILABLE) || (defined(AMD_WMMA_AVAILABLE) && defined(RDNA4)) || defined(AMD_MFMA_AVAILABLE))
// Skip unused kernel variants for faster compilation:
if (use_logit_softcap && !(DKQ == 128 || DKQ == 256)) {
if (use_logit_softcap && !(DKQ == 128 || DKQ == 256 || DKQ == 512)) {
NO_DEVICE_CODE;
return;
}
@ -1815,6 +1834,15 @@ DECL_FATTN_MMA_F16_CASE_ALL_NCOLS2(112, 112, 64)
DECL_FATTN_MMA_F16_CASE_ALL_NCOLS2(128, 128, 64)
DECL_FATTN_MMA_F16_CASE_ALL_NCOLS2(256, 256, 64)
extern DECL_FATTN_MMA_F16_CASE(512, 512, 2, 4);
extern DECL_FATTN_MMA_F16_CASE(512, 512, 4, 4);
extern DECL_FATTN_MMA_F16_CASE(512, 512, 8, 4);
extern DECL_FATTN_MMA_F16_CASE(512, 512, 16, 4);
extern DECL_FATTN_MMA_F16_CASE(512, 512, 1, 8);
extern DECL_FATTN_MMA_F16_CASE(512, 512, 2, 8);
extern DECL_FATTN_MMA_F16_CASE(512, 512, 4, 8);
extern DECL_FATTN_MMA_F16_CASE(512, 512, 8, 8);
// The number of viable configurations for Deepseek is very limited:
extern DECL_FATTN_MMA_F16_CASE(576, 512, 1, 16);
extern DECL_FATTN_MMA_F16_CASE(576, 512, 2, 16);

View File

@ -38,6 +38,10 @@ void ggml_cuda_flash_attn_ext_tile(ggml_backend_cuda_context & ctx, ggml_tensor
GGML_ASSERT(V->ne[0] == K->ne[0]);
ggml_cuda_flash_attn_ext_tile_case<256, 256>(ctx, dst);
} break;
case 512: {
GGML_ASSERT(V->ne[0] == K->ne[0]);
ggml_cuda_flash_attn_ext_tile_case<512, 512>(ctx, dst);
} break;
case 576: {
GGML_ASSERT(V->ne[0] == 512);
ggml_cuda_flash_attn_ext_tile_case<576, 512>(ctx, dst);

View File

@ -68,6 +68,10 @@ static constexpr __host__ __device__ uint32_t ggml_cuda_fattn_tile_get_config_nv
GGML_CUDA_FATTN_TILE_CONFIG_CASE(256, 256, 16, 256, 2, 64, 64)
GGML_CUDA_FATTN_TILE_CONFIG_CASE(256, 256, 32, 256, 2, 64, 64)
GGML_CUDA_FATTN_TILE_CONFIG_CASE(512, 512, 4, 128, 2, 64, 64)
GGML_CUDA_FATTN_TILE_CONFIG_CASE(512, 512, 8, 256, 2, 64, 64)
GGML_CUDA_FATTN_TILE_CONFIG_CASE(512, 512, 16, 256, 2, 64, 64)
GGML_CUDA_FATTN_TILE_CONFIG_CASE(576, 512, 4, 128, 2, 64, 64)
GGML_CUDA_FATTN_TILE_CONFIG_CASE(576, 512, 8, 256, 2, 64, 64)
GGML_CUDA_FATTN_TILE_CONFIG_CASE(576, 512, 16, 256, 2, 64, 64)
@ -124,6 +128,10 @@ static constexpr __host__ __device__ uint32_t ggml_cuda_fattn_tile_get_config_nv
GGML_CUDA_FATTN_TILE_CONFIG_CASE(256, 256, 16, 256, 2, 32, 128)
GGML_CUDA_FATTN_TILE_CONFIG_CASE(256, 256, 32, 256, 2, 32, 64)
GGML_CUDA_FATTN_TILE_CONFIG_CASE(512, 512, 4, 128, 2, 32, 64)
GGML_CUDA_FATTN_TILE_CONFIG_CASE(512, 512, 8, 256, 2, 32, 64)
GGML_CUDA_FATTN_TILE_CONFIG_CASE(512, 512, 16, 256, 2, 32, 64)
GGML_CUDA_FATTN_TILE_CONFIG_CASE(576, 512, 4, 128, 2, 32, 64)
GGML_CUDA_FATTN_TILE_CONFIG_CASE(576, 512, 8, 256, 2, 32, 64)
GGML_CUDA_FATTN_TILE_CONFIG_CASE(576, 512, 16, 256, 2, 32, 64)
@ -187,6 +195,11 @@ static constexpr __host__ __device__ uint32_t ggml_cuda_fattn_tile_get_config_am
GGML_CUDA_FATTN_TILE_CONFIG_CASE(256, 256, 16, 256, 2, 32, 128)
GGML_CUDA_FATTN_TILE_CONFIG_CASE(256, 256, 32, 256, 2, 32, 128)
GGML_CUDA_FATTN_TILE_CONFIG_CASE(512, 512, 4, 128, 2, 64, 64)
GGML_CUDA_FATTN_TILE_CONFIG_CASE(512, 512, 8, 256, 2, 64, 64)
GGML_CUDA_FATTN_TILE_CONFIG_CASE(512, 512, 16, 256, 2, 64, 64)
GGML_CUDA_FATTN_TILE_CONFIG_CASE(512, 512, 32, 512, 1, 128, 64)
GGML_CUDA_FATTN_TILE_CONFIG_CASE(576, 512, 4, 128, 2, 64, 64)
GGML_CUDA_FATTN_TILE_CONFIG_CASE(576, 512, 8, 256, 2, 64, 64)
GGML_CUDA_FATTN_TILE_CONFIG_CASE(576, 512, 16, 256, 2, 64, 64)
@ -251,6 +264,11 @@ static constexpr __host__ __device__ uint32_t ggml_cuda_fattn_tile_get_config_am
GGML_CUDA_FATTN_TILE_CONFIG_CASE(256, 256, 16, 256, 5, 32, 256)
GGML_CUDA_FATTN_TILE_CONFIG_CASE(256, 256, 32, 256, 3, 64, 128)
GGML_CUDA_FATTN_TILE_CONFIG_CASE(512, 512, 4, 128, 2, 64, 64)
GGML_CUDA_FATTN_TILE_CONFIG_CASE(512, 512, 8, 256, 2, 64, 64)
GGML_CUDA_FATTN_TILE_CONFIG_CASE(512, 512, 16, 256, 4, 64, 64)
GGML_CUDA_FATTN_TILE_CONFIG_CASE(512, 512, 32, 256, 2, 128, 64)
GGML_CUDA_FATTN_TILE_CONFIG_CASE(576, 512, 4, 128, 2, 64, 64)
GGML_CUDA_FATTN_TILE_CONFIG_CASE(576, 512, 8, 256, 2, 64, 64)
GGML_CUDA_FATTN_TILE_CONFIG_CASE(576, 512, 16, 256, 4, 64, 64)
@ -767,7 +785,7 @@ static __global__ void flash_attn_tile(
#ifdef GGML_USE_WMMA_FATTN
(ncols2 != 1 && DV != 40 && DV != 72 && DV != 512) ||
#endif // GGML_USE_WMMA_FATTN
(use_logit_softcap && !(DV == 128 || DV == 256))
(use_logit_softcap && !(DV == 128 || DV == 256 || DV == 512))
) {
GGML_UNUSED_VARS(Q, K, V, mask, sinks, KV_max, dst, dst_meta, scale,
max_bias, m0, m1, n_head_log2, logit_softcap,
@ -1192,7 +1210,7 @@ static void launch_fattn_tile_switch_ncols2(ggml_backend_cuda_context & ctx, ggm
const int gqa_limit = nvidia && gqa_ratio <= 4 && DV <= 256 ? 16 : INT_MAX;
const bool use_gqa_opt = mask && max_bias == 0.0f && Q->ne[1] <= gqa_limit && K->ne[1] % FATTN_KQ_STRIDE == 0;
if constexpr (DV == 512) {
if constexpr (DKQ == 576) {
if (use_gqa_opt && gqa_ratio % 16 == 0) {
launch_fattn_tile_switch_ncols1<DKQ, DV, 16, use_logit_softcap>(ctx, dst);
return;
@ -1203,7 +1221,7 @@ static void launch_fattn_tile_switch_ncols2(ggml_backend_cuda_context & ctx, ggm
}
}
if constexpr (DV <= 256) {
if constexpr (DKQ <= 512) {
if (use_gqa_opt && gqa_ratio % 8 == 0) {
launch_fattn_tile_switch_ncols1<DKQ, DV, 8, use_logit_softcap>(ctx, dst);
return;
@ -1214,13 +1232,15 @@ static void launch_fattn_tile_switch_ncols2(ggml_backend_cuda_context & ctx, ggm
return;
}
if (use_gqa_opt && gqa_ratio % 2 == 0) {
launch_fattn_tile_switch_ncols1<DKQ, DV, 2, use_logit_softcap>(ctx, dst);
if constexpr (DV <= 256) {
if (use_gqa_opt && gqa_ratio % 2 == 0) {
launch_fattn_tile_switch_ncols1<DKQ, DV, 2, use_logit_softcap>(ctx, dst);
return;
}
launch_fattn_tile_switch_ncols1<DKQ, DV, 1, use_logit_softcap>(ctx, dst);
return;
}
launch_fattn_tile_switch_ncols1<DKQ, DV, 1, use_logit_softcap>(ctx, dst);
return;
}
GGML_ABORT("fatal error");
}
@ -1255,4 +1275,5 @@ extern DECL_FATTN_TILE_CASE( 96, 96);
extern DECL_FATTN_TILE_CASE(112, 112);
extern DECL_FATTN_TILE_CASE(128, 128);
extern DECL_FATTN_TILE_CASE(256, 256);
extern DECL_FATTN_TILE_CASE(512, 512);
extern DECL_FATTN_TILE_CASE(576, 512);

View File

@ -135,6 +135,10 @@ static void ggml_cuda_flash_attn_ext_mma_f16(ggml_backend_cuda_context & ctx, gg
GGML_ASSERT(V->ne[0] == 256);
ggml_cuda_flash_attn_ext_mma_f16_switch_ncols2<256, 256>(ctx, dst);
break;
case 512:
GGML_ASSERT(V->ne[0] == 512);
ggml_cuda_flash_attn_ext_mma_f16_switch_ncols2<512, 512>(ctx, dst);
break;
case 576: {
// For Deepseek, go straight to the ncols1 switch to avoid compiling unnecessary kernels.
GGML_ASSERT(V->ne[0] == 512);
@ -336,7 +340,8 @@ static best_fattn_kernel ggml_cuda_get_best_fattn_kernel(const int device, const
case 128:
case 112:
case 256:
if (V->ne[0] != K->ne[0]) {
case 512:
if (!gqa_opt_applies) {
return BEST_FATTN_KERNEL_NONE;
}
break;
@ -424,7 +429,7 @@ static best_fattn_kernel ggml_cuda_get_best_fattn_kernel(const int device, const
}
// Use the WMMA kernel if possible:
if (ggml_cuda_should_use_wmma_fattn(cc) && K->ne[1] % FATTN_KQ_STRIDE == 0 && Q->ne[0] != 40 && Q->ne[0] != 72 && Q->ne[0] != 576) {
if (ggml_cuda_should_use_wmma_fattn(cc) && K->ne[1] % FATTN_KQ_STRIDE == 0 && Q->ne[0] != 40 && Q->ne[0] != 72 && Q->ne[0] != 512 && Q->ne[0] != 576) {
if (can_use_vector_kernel && Q->ne[1] <= 2) {
return BEST_FATTN_KERNEL_VEC;
}
@ -457,7 +462,7 @@ static best_fattn_kernel ggml_cuda_get_best_fattn_kernel(const int device, const
}
// Use MFMA flash attention for CDNA (MI100+):
if (amd_mfma_available(cc) && Q->ne[0] != 40 && Q->ne[0] != 72 && Q->ne[0] != 256 && Q->ne[0] != 576) {
if (amd_mfma_available(cc) && Q->ne[0] != 40 && Q->ne[0] != 72 && Q->ne[0] != 256 && Q->ne[0] != 512 && Q->ne[0] != 576) {
const int64_t eff_nq = Q->ne[1] * (gqa_opt_applies ? gqa_ratio : 1);
// MMA vs tile crossover benchmarked on MI300X @ d32768:
// hsk=64 (gqa=4): MMA wins at eff >= 128 (+11%)

View File

@ -8,3 +8,4 @@ DECL_FATTN_MMA_F16_CASE(96, 96, 1, 8);
DECL_FATTN_MMA_F16_CASE(112, 112, 1, 8);
DECL_FATTN_MMA_F16_CASE(128, 128, 1, 8);
DECL_FATTN_MMA_F16_CASE(256, 256, 1, 8);
DECL_FATTN_MMA_F16_CASE(512, 512, 1, 8);

View File

@ -8,4 +8,5 @@ DECL_FATTN_MMA_F16_CASE(96, 96, 16, 4);
DECL_FATTN_MMA_F16_CASE(112, 112, 16, 4);
DECL_FATTN_MMA_F16_CASE(128, 128, 16, 4);
DECL_FATTN_MMA_F16_CASE(256, 256, 16, 4);
DECL_FATTN_MMA_F16_CASE(512, 512, 16, 4);
DECL_FATTN_MMA_F16_CASE(576, 512, 16, 4);

View File

@ -8,4 +8,5 @@ DECL_FATTN_MMA_F16_CASE(96, 96, 2, 4);
DECL_FATTN_MMA_F16_CASE(112, 112, 2, 4);
DECL_FATTN_MMA_F16_CASE(128, 128, 2, 4);
DECL_FATTN_MMA_F16_CASE(256, 256, 2, 4);
DECL_FATTN_MMA_F16_CASE(512, 512, 2, 4);
DECL_FATTN_MMA_F16_CASE(576, 512, 2, 4);

View File

@ -8,3 +8,4 @@ DECL_FATTN_MMA_F16_CASE(96, 96, 2, 8);
DECL_FATTN_MMA_F16_CASE(112, 112, 2, 8);
DECL_FATTN_MMA_F16_CASE(128, 128, 2, 8);
DECL_FATTN_MMA_F16_CASE(256, 256, 2, 8);
DECL_FATTN_MMA_F16_CASE(512, 512, 2, 8);

View File

@ -8,4 +8,5 @@ DECL_FATTN_MMA_F16_CASE(96, 96, 4, 4);
DECL_FATTN_MMA_F16_CASE(112, 112, 4, 4);
DECL_FATTN_MMA_F16_CASE(128, 128, 4, 4);
DECL_FATTN_MMA_F16_CASE(256, 256, 4, 4);
DECL_FATTN_MMA_F16_CASE(512, 512, 4, 4);
DECL_FATTN_MMA_F16_CASE(576, 512, 4, 4);

View File

@ -8,3 +8,4 @@ DECL_FATTN_MMA_F16_CASE(96, 96, 4, 8);
DECL_FATTN_MMA_F16_CASE(112, 112, 4, 8);
DECL_FATTN_MMA_F16_CASE(128, 128, 4, 8);
DECL_FATTN_MMA_F16_CASE(256, 256, 4, 8);
DECL_FATTN_MMA_F16_CASE(512, 512, 4, 8);

View File

@ -8,4 +8,5 @@ DECL_FATTN_MMA_F16_CASE(96, 96, 8, 4);
DECL_FATTN_MMA_F16_CASE(112, 112, 8, 4);
DECL_FATTN_MMA_F16_CASE(128, 128, 8, 4);
DECL_FATTN_MMA_F16_CASE(256, 256, 8, 4);
DECL_FATTN_MMA_F16_CASE(512, 512, 8, 4);
DECL_FATTN_MMA_F16_CASE(576, 512, 8, 4);

View File

@ -8,3 +8,4 @@ DECL_FATTN_MMA_F16_CASE(96, 96, 8, 8);
DECL_FATTN_MMA_F16_CASE(112, 112, 8, 8);
DECL_FATTN_MMA_F16_CASE(128, 128, 8, 8);
DECL_FATTN_MMA_F16_CASE(256, 256, 8, 8);
DECL_FATTN_MMA_F16_CASE(512, 512, 8, 8);

View File

@ -0,0 +1,5 @@
// This file has been autogenerated by generate_cu_files.py, do not edit manually.
#include "../fattn-tile.cuh"
DECL_FATTN_TILE_CASE(512, 512);

View File

@ -3,7 +3,7 @@
from glob import glob
import os
HEAD_SIZES_KQ = [40, 64, 72, 80, 96, 112, 128, 256, 576]
HEAD_SIZES_KQ = [40, 64, 72, 80, 96, 112, 128, 256, 512, 576]
TYPES_KV = ["GGML_TYPE_F16", "GGML_TYPE_Q4_0", "GGML_TYPE_Q4_1", "GGML_TYPE_Q5_0", "GGML_TYPE_Q5_1", "GGML_TYPE_Q8_0", "GGML_TYPE_BF16"]
@ -83,6 +83,8 @@ for ncols in [8, 16, 32, 64]:
continue
if head_size_kq == 72:
continue
if head_size_kq == 512 and ncols2 not in (4, 8):
continue
if head_size_kq != 576 and ncols2 in (16, 32):
continue
if head_size_kq == 576 and ncols2 not in (4, 16, 32):