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CUDA: Faster FlashAttention kernel #6374

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Merged
merged 10 commits into from
Apr 2, 2024
Merged

CUDA: Faster FlashAttention kernel #6374

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912a6aa
CUDA: faster FlashAttention, kernel for bs == 1
JohannesGaessler Mar 29, 2024
e3794ef
16 cols for Phi-2
JohannesGaessler Mar 30, 2024
3a44bfe
no vec for hs, no hs==256 ncols==32 for Volta
JohannesGaessler Mar 30, 2024
824adc9
adjust kernel selection logic
JohannesGaessler Mar 31, 2024
4a4e549
4 warps, 256 stride for all D
JohannesGaessler Mar 31, 2024
b3e66f1
no ncols == 64
JohannesGaessler Apr 1, 2024
822d338
Multiple parallel blocks for batch size 1
JohannesGaessler Apr 1, 2024
ef7282a
fix compile warnings
JohannesGaessler Apr 2, 2024
46968c9
fix excessive KQ_b loads
JohannesGaessler Apr 2, 2024
b446893
fix cmake build
JohannesGaessler Apr 2, 2024
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27 changes: 13 additions & 14 deletions ggml-cuda/common.cuh
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Original file line number Diff line number Diff line change
Expand Up @@ -141,6 +141,7 @@
#define CC_PASCAL 600
#define MIN_CC_DP4A 610 // minimum compute capability for __dp4a, an intrinsic for byte-wise dot products
#define CC_VOLTA 700
#define CC_AMPERE 800
#define CC_OFFSET_AMD 1000000
#define CC_RDNA1 (CC_OFFSET_AMD + 1010)
#define CC_RDNA2 (CC_OFFSET_AMD + 1030)
Expand Down Expand Up @@ -270,7 +271,6 @@ static __device__ __forceinline__ float2 warp_reduce_sum(float2 a) {
return a;
}

#ifdef GGML_CUDA_F16
static __device__ __forceinline__ half2 warp_reduce_sum(half2 a) {
#if !(defined(GGML_USE_HIPBLAS) && defined(__HIP_PLATFORM_AMD__)) && __CUDA_ARCH__ >= CC_PASCAL
#pragma unroll
Expand All @@ -283,7 +283,6 @@ static __device__ __forceinline__ half2 warp_reduce_sum(half2 a) {
NO_DEVICE_CODE;
#endif // !(defined(GGML_USE_HIPBLAS) && defined(__HIP_PLATFORM_AMD__)) && __CUDA_ARCH__ >= CC_PASCAL
}
#endif // GGML_CUDA_F16

static __device__ __forceinline__ float warp_reduce_max(float x) {
#pragma unroll
Expand All @@ -293,18 +292,18 @@ static __device__ __forceinline__ float warp_reduce_max(float x) {
return x;
}

//static __device__ __forceinline__ half2 warp_reduce_max(half2 x) {
//#if !(defined(GGML_USE_HIPBLAS) && defined(__HIP_PLATFORM_AMD__)) && __CUDA_ARCH__ >= CC_PASCAL && CUDART_VERSION >= CUDART_HMAX
//#pragma unroll
// for (int mask = 16; mask > 0; mask >>= 1) {
// x = __hmax2(x, __shfl_xor_sync(0xffffffff, x, mask, 32));
// }
// return x;
//#else
// GGML_UNUSED(x);
// NO_DEVICE_CODE;
//#endif // !(defined(GGML_USE_HIPBLAS) && defined(__HIP_PLATFORM_AMD__)) && __CUDA_ARCH__ >= CC_PASCAL && CUDART_VERSION >= CUDART_HMAX
//}
static __device__ __forceinline__ half2 warp_reduce_max(half2 x) {
#if !(defined(GGML_USE_HIPBLAS) && defined(__HIP_PLATFORM_AMD__)) && __CUDA_ARCH__ >= CC_PASCAL && CUDART_VERSION >= CUDART_HMAX
#pragma unroll
for (int mask = 16; mask > 0; mask >>= 1) {
x = __hmax2(x, __shfl_xor_sync(0xffffffff, x, mask, 32));
}
return x;
#else
GGML_UNUSED(x);
NO_DEVICE_CODE;
#endif // !(defined(GGML_USE_HIPBLAS) && defined(__HIP_PLATFORM_AMD__)) && __CUDA_ARCH__ >= CC_PASCAL && CUDART_VERSION >= CUDART_HMAX
}


#if defined(GGML_USE_HIPBLAS)
Expand Down
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