Convert vector to f16 for dequantize mul mat vec (#1913)

* Convert vector to f16 for dmmv

* compile option

* Added compilation option description to README

* Changed cmake CUDA_ARCHITECTURES from "OFF" to "native"

1 files changed, 139 insertions, 63 deletions

diff --git a/ggml-cuda.cu b/ggml-cuda.cu
index 16488b9..9ebc57a 100644
--- a/ggml-cuda.cu
+++ b/ggml-cuda.cu
@@ -50,7 +50,15 @@ static_assert(sizeof(half) == sizeof(ggml_fp16_t), "wrong fp16 size");
     } while (0)
 #endif // CUDART_VERSION >= 11
 
-typedef void (*dequantize_kernel_t)(const void * vx, const int ib, const int iqs, float & v0, float & v1);
+#ifdef GGML_CUDA_DMMV_F16
+typedef half dfloat; // dequantize float
+typedef half2 dfloat2;
+#else
+typedef float dfloat; // dequantize float
+typedef float2 dfloat2;
+#endif //GGML_CUDA_DMMV_F16
+
+typedef void (*dequantize_kernel_t)(const void * vx, const int ib, const int iqs, dfloat2 & v);
 typedef void (*to_fp32_cuda_t)(const void * x, float * y, int k, cudaStream_t stream);
 typedef void (*dot_kernel_k_t)(const void * vx, const int ib, const int iqs, const float * y, float & v);
 typedef void (*cpy_kernel_t)(const char * cx, char * cdst);
@@ -234,82 +242,106 @@ static __global__ void rms_norm_f32(const float * x, float * dst, const int ncol
     }
 }
 
-static __device__ void dequantize_q4_0(const void * vx, const int ib, const int iqs, float & v0, float & v1){
+static __device__ __forceinline__ void dequantize_q4_0(const void * vx, const int ib, const int iqs, dfloat2 & v){
     const block_q4_0 * x = (const block_q4_0 *) vx;
 
-    const float d = x[ib].d;
+    const dfloat d = x[ib].d;
 
-    const uint8_t vui = x[ib].qs[iqs];
+    const int vui = x[ib].qs[iqs];
 
-    const int8_t vi0 = vui & 0xF;
-    const int8_t vi1 = vui >> 4;
+    v.x = vui & 0xF;
+    v.y = vui >> 4;
 
-    v0 = (vi0 - 8)*d;
-    v1 = (vi1 - 8)*d;
+#ifdef GGML_CUDA_DMMV_F16
+    v = __hsub2(v, {8.0f, 8.0f});
+    v = __hmul2(v, {d, d});
+#else
+    v.x = (v.x - 8.0f) * d;
+    v.y = (v.y - 8.0f) * d;
+#endif // GGML_CUDA_DMMV_F16
 }
 
-static __device__ void dequantize_q4_1(const void * vx, const int ib, const int iqs, float & v0, float & v1){
+static __device__ __forceinline__ void dequantize_q4_1(const void * vx, const int ib, const int iqs, dfloat2 & v){
     const block_q4_1 * x = (const block_q4_1 *) vx;
 
-    const float d = x[ib].d;
-    const float m = x[ib].m;
+    const dfloat d = x[ib].d;
+    const dfloat m = x[ib].m;
 
-    const uint8_t vui = x[ib].qs[iqs];
+    const int vui = x[ib].qs[iqs];
 
-    const int8_t vi0 = vui & 0xF;
-    const int8_t vi1 = vui >> 4;
+    v.x = vui & 0xF;
+    v.y = vui >> 4;
 
-    v0 = vi0*d + m;
-    v1 = vi1*d + m;
+#ifdef GGML_CUDA_DMMV_F16
+    v = __hmul2(v, {d, d});
+    v = __hadd2(v, {m, m});
+#else
+    v.x = (v.x * d) + m;
+    v.y = (v.y * d) + m;
+#endif // GGML_CUDA_DMMV_F16
 }
 
-static __device__ void dequantize_q5_0(const void * vx, const int ib, const int iqs, float & v0, float & v1){
+static __device__ __forceinline__ void dequantize_q5_0(const void * vx, const int ib, const int iqs, dfloat2 & v){
     const block_q5_0 * x = (const block_q5_0 *) vx;
 
-    const float d = x[ib].d;
+    const dfloat d = x[ib].d;
 
     uint32_t qh;
     memcpy(&qh, x[ib].qh, sizeof(qh));
 
-    const uint8_t xh_0 = ((qh >> (iqs +  0)) << 4) & 0x10;
-    const uint8_t xh_1 = ((qh >> (iqs + 12))     ) & 0x10;
+    const int xh_0 = ((qh >> (iqs +  0)) << 4) & 0x10;
+    const int xh_1 = ((qh >> (iqs + 12))     ) & 0x10;
 
-    const int32_t x0 = ((x[ib].qs[iqs] & 0xf) | xh_0) - 16;
-    const int32_t x1 = ((x[ib].qs[iqs] >>  4) | xh_1) - 16;
+    v.x = ((x[ib].qs[iqs] & 0xf) | xh_0);
+    v.y = ((x[ib].qs[iqs] >>  4) | xh_1);
 
-    v0 = x0*d;
-    v1 = x1*d;
+#ifdef GGML_CUDA_DMMV_F16
+    v = __hsub2(v, {16.0f, 16.0f});
+    v = __hmul2(v, {d, d});
+#else
+    v.x = (v.x - 16.0f) * d;
+    v.y = (v.y - 16.0f) * d;
+#endif // GGML_CUDA_DMMV_F16
 }
 
-static __device__ void dequantize_q5_1(const void * vx, const int ib, const int iqs, float & v0, float & v1){
+static __device__ __forceinline__ void dequantize_q5_1(const void * vx, const int ib, const int iqs, dfloat2 & v){
     const block_q5_1 * x = (const block_q5_1 *) vx;
 
-    const float d = x[ib].d;
-    const float m = x[ib].m;
+    const dfloat d = x[ib].d;
+    const dfloat m = x[ib].m;
 
     uint32_t qh;
     memcpy(&qh, x[ib].qh, sizeof(qh));
 
-    const uint8_t xh_0 = ((qh >> (iqs +  0)) << 4) & 0x10;
-    const uint8_t xh_1 = ((qh >> (iqs + 12))     ) & 0x10;
+    const int xh_0 = ((qh >> (iqs +  0)) << 4) & 0x10;
+    const int xh_1 = ((qh >> (iqs + 12))     ) & 0x10;
 
-    const int32_t x0 = ((x[ib].qs[iqs] & 0xf) | xh_0);
-    const int32_t x1 = ((x[ib].qs[iqs] >>  4) | xh_1);
+    v.x = ((x[ib].qs[iqs] & 0xf) | xh_0);
+    v.y = ((x[ib].qs[iqs] >>  4) | xh_1);
 
-    v0 = x0*d + m;
-    v1 = x1*d + m;
+#ifdef GGML_CUDA_DMMV_F16
+    v = __hmul2(v, {d, d});
+    v = __hadd2(v, {m, m});
+#else
+    v.x = (v.x * d) + m;
+    v.y = (v.y * d) + m;
+#endif // GGML_CUDA_DMMV_F16
 }
 
-static __device__ void dequantize_q8_0(const void * vx, const int ib, const int iqs, float & v0, float & v1){
+static __device__ __forceinline__ void dequantize_q8_0(const void * vx, const int ib, const int iqs, dfloat2 & v){
     const block_q8_0 * x = (const block_q8_0 *) vx;
 
-    const float d = x[ib].d;
+    const dfloat d = x[ib].d;
 
-    const int8_t vi0 = x[ib].qs[iqs + 0];
-    const int8_t vi1 = x[ib].qs[iqs + 1];
+    v.x = x[ib].qs[iqs + 0];
+    v.y = x[ib].qs[iqs + 1];
 
-    v0 = vi0*d;
-    v1 = vi1*d;
+#ifdef GGML_CUDA_DMMV_F16
+    v = __hmul2(v, {d, d});
+#else
+    v.x *= d;
+    v.y *= d;
+#endif // GGML_CUDA_DMMV_F16
 }
 
 //================================== k-quants
@@ -843,11 +875,12 @@ static __global__ void dequantize_mul_mat_vec_q6_k(const void * vx, const float
     }
 }
 
-static __device__ void convert_f16(const void * vx, const int ib, const int iqs, float & v0, float & v1){
+static __device__ void convert_f16(const void * vx, const int ib, const int iqs, dfloat2 & v){
     const half * x = (const half *) vx;
 
-    v0 = __half2float(x[ib + iqs + 0]);
-    v1 = __half2float(x[ib + iqs + 1]);
+    // automatic half -> float type cast if dfloat == float
+    v.x = x[ib + iqs + 0];
+    v.y = x[ib + iqs + 1];
 }
 
 template <int qk, int qr, dequantize_kernel_t dequantize_kernel>
@@ -864,13 +897,15 @@ static __global__ void dequantize_block(const void * vx, float * y, const int k)
     const int y_offset = qr == 1 ? 1 : qk/2;
 
     // dequantize
-    float & v0 = y[iybs + iqs + 0];
-    float & v1 = y[iybs + iqs + y_offset];
-    dequantize_kernel(vx, ib, iqs, v0, v1);
+    dfloat2 v;
+    dequantize_kernel(vx, ib, iqs, v);
+
+    y[iybs + iqs + 0]        = v.x;
+    y[iybs + iqs + y_offset] = v.y;
 }
 
 template <int qk, int qr, dequantize_kernel_t dequantize_kernel>
-static __global__ void dequantize_mul_mat_vec(const void * vx, const float * y, float * dst, const int ncols, const int nrows) {
+static __global__ void dequantize_mul_mat_vec(const void * vx, const dfloat * y, float * dst, const int ncols, const int nrows) {
     // qk = quantized weights per x block
     // qr = number of quantized weights per data value in x block
     const int row = blockIdx.y*blockDim.y + threadIdx.y;
@@ -885,7 +920,12 @@ static __global__ void dequantize_mul_mat_vec(const void * vx, const float * y,
     const int vals_per_iter = iter_stride / WARP_SIZE; // num quantized vals per thread and i iter
     const int y_offset = qr == 1 ? 1 : qk/2;
 
-    float tmp = 0.0f; // partial sum for thread in warp
+// partial sum for each thread
+#ifdef GGML_CUDA_DMMV_F16
+    half2 tmp = {0.0f, 0.0f}; // two sums for f16 to take advantage of half2 intrinsics
+#else
+    float tmp = 0.0f;
+#endif // GGML_CUDA_DMMV_F16
 
     for (int i = 0; i < ncols; i += iter_stride) {
         const int col = i + vals_per_iter*tid;
@@ -899,14 +939,21 @@ static __global__ void dequantize_mul_mat_vec(const void * vx, const float * y,
             // process 2 vals per j iter
 
             // dequantize
-            float v0, v1;
-            dequantize_kernel(vx, ib, iqs + j/qr, v0, v1);
             // for qr = 2 the iqs needs to increase by 1 per j iter because 2 weights per data val
+            dfloat2 v;
+            dequantize_kernel(vx, ib, iqs + j/qr, v);
 
             // matrix multiplication
-            tmp += v0 * y[iybs + iqs + j/qr + 0];
-            tmp += v1 * y[iybs + iqs + j/qr + y_offset];
             // for qr = 2 the y index needs to increase by 1 per j iter because of y_offset = qk/2
+#ifdef GGML_CUDA_DMMV_F16
+            tmp += __hmul2(v, {
+                y[iybs + iqs + j/qr + 0],
+                y[iybs + iqs + j/qr + y_offset]
+            });
+#else
+            tmp += v.x * y[iybs + iqs + j/qr + 0];
+            tmp += v.y * y[iybs + iqs + j/qr + y_offset];
+#endif // GGML_CUDA_DMMV_F16
         }
     }
 
@@ -918,7 +965,11 @@ static __global__ void dequantize_mul_mat_vec(const void * vx, const float * y,
     }
 
     if (tid == 0) {
+#ifdef GGML_CUDA_DMMV_F16
+        dst[row] = tmp.x + tmp.y;
+#else
         dst[row] = tmp;
+#endif // GGML_CUDA_DMMV_F16
     }
 }
 
@@ -1213,7 +1264,7 @@ static void dequantize_row_q6_K_cuda(const void * vx, float * y, const int k, cu
     dequantize_block_q6_K<<<nb, 64, 0, stream>>>(vx, y);
 }
 
-static void dequantize_mul_mat_vec_q4_0_cuda(const void * vx, const float * y, float * dst, const int ncols, const int nrows, cudaStream_t stream) {
+static void dequantize_mul_mat_vec_q4_0_cuda(const void * vx, const dfloat * y, float * dst, const int ncols, const int nrows, cudaStream_t stream) {
     GGML_ASSERT(ncols % GGML_CUDA_DMMV_X == 0);
     const int block_num_y = (nrows + GGML_CUDA_DMMV_Y - 1) / GGML_CUDA_DMMV_Y;
     const dim3 block_nums(1, block_num_y, 1);
@@ -1222,7 +1273,7 @@ static void dequantize_mul_mat_vec_q4_0_cuda(const void * vx, const float * y, f
         <<<block_nums, block_dims, 0, stream>>>(vx, y, dst, ncols, nrows);
 }
 
-static void dequantize_mul_mat_vec_q4_1_cuda(const void * vx, const float * y, float * dst, const int ncols, const int nrows, cudaStream_t stream) {
+static void dequantize_mul_mat_vec_q4_1_cuda(const void * vx, const dfloat * y, float * dst, const int ncols, const int nrows, cudaStream_t stream) {
     GGML_ASSERT(ncols % GGML_CUDA_DMMV_X == 0);
     const int block_num_y = (nrows + GGML_CUDA_DMMV_Y - 1) / GGML_CUDA_DMMV_Y;
     const dim3 block_nums(1, block_num_y, 1);
@@ -1231,7 +1282,7 @@ static void dequantize_mul_mat_vec_q4_1_cuda(const void * vx, const float * y, f
         <<<block_nums, block_dims, 0, stream>>>(vx, y, dst, ncols, nrows);
 }
 
-static void dequantize_mul_mat_vec_q5_0_cuda(const void * vx, const float * y, float * dst, const int ncols, const int nrows, cudaStream_t stream) {
+static void dequantize_mul_mat_vec_q5_0_cuda(const void * vx, const dfloat * y, float * dst, const int ncols, const int nrows, cudaStream_t stream) {
     GGML_ASSERT(ncols % GGML_CUDA_DMMV_X == 0);
     const int block_num_y = (nrows + GGML_CUDA_DMMV_Y - 1) / GGML_CUDA_DMMV_Y;
     const dim3 block_nums(1, block_num_y, 1);
@@ -1240,7 +1291,7 @@ static void dequantize_mul_mat_vec_q5_0_cuda(const void * vx, const float * y, f
         <<<block_nums, block_dims, 0, stream>>>(vx, y, dst, ncols, nrows);
 }
 
-static void dequantize_mul_mat_vec_q5_1_cuda(const void * vx, const float * y, float * dst, const int ncols, const int nrows, cudaStream_t stream) {
+static void dequantize_mul_mat_vec_q5_1_cuda(const void * vx, const dfloat * y, float * dst, const int ncols, const int nrows, cudaStream_t stream) {
     GGML_ASSERT(ncols % GGML_CUDA_DMMV_X == 0);
     const int block_num_y = (nrows + GGML_CUDA_DMMV_Y - 1) / GGML_CUDA_DMMV_Y;
     const dim3 block_nums(1, block_num_y, 1);
@@ -1249,7 +1300,7 @@ static void dequantize_mul_mat_vec_q5_1_cuda(const void * vx, const float * y, f
         <<<block_nums, block_dims, 0, stream>>>(vx, y, dst, ncols, nrows);
 }
 
-static void dequantize_mul_mat_vec_q8_0_cuda(const void * vx, const float * y, float * dst, const int ncols, const int nrows, cudaStream_t stream) {
+static void dequantize_mul_mat_vec_q8_0_cuda(const void * vx, const dfloat * y, float * dst, const int ncols, const int nrows, cudaStream_t stream) {
     GGML_ASSERT(ncols % GGML_CUDA_DMMV_X == 0);
     const int block_num_y = (nrows + GGML_CUDA_DMMV_Y - 1) / GGML_CUDA_DMMV_Y;
     const dim3 block_nums(1, block_num_y, 1);
@@ -1299,7 +1350,7 @@ static void convert_fp16_to_fp32_cuda(const void * vx, float * y, const int k, c
     dequantize_block<1, 1, convert_f16><<<num_blocks, CUDA_DEQUANTIZE_BLOCK_SIZE, 0, stream>>>(vx, y, k);
 }
 
-static void convert_mul_mat_vec_f16_cuda(const void * vx, const float * y, float * dst, const int ncols, const int nrows, cudaStream_t stream) {
+static void convert_mul_mat_vec_f16_cuda(const void * vx, const dfloat * y, float * dst, const int ncols, const int nrows, cudaStream_t stream) {
     GGML_ASSERT(ncols % GGML_CUDA_DMMV_X == 0);
     const int block_num_y = (nrows + GGML_CUDA_DMMV_Y - 1) / GGML_CUDA_DMMV_Y;
     const dim3 block_nums(1, block_num_y, 1);
@@ -1714,21 +1765,40 @@ inline void ggml_cuda_op_dequantize_mul_mat_vec(
     const int64_t ne00 = src0->ne[0];
     const int64_t nrows = i01_high - i01_low;
 
+// on some GPUs it is faster to convert src1 to half and to use half precision intrinsics
+#ifdef GGML_CUDA_DMMV_F16
+    size_t ash;
+    dfloat * src1_dfloat = nullptr; // dfloat == half
+
+    bool src1_convert_f16 = src0->type == GGML_TYPE_Q4_0 || src0->type == GGML_TYPE_Q4_1 ||
+        src0->type == GGML_TYPE_Q5_0 || src0->type == GGML_TYPE_Q5_1 ||
+        src0->type == GGML_TYPE_Q8_0 || src0->type == GGML_TYPE_F16;
+
+    if (src1_convert_f16) {
+        src1_dfloat = (half *) ggml_cuda_pool_malloc(ne00*sizeof(half), &ash);
+        ggml_cpy_f32_f16_cuda((char *) src1_ddf_i, (char *) src1_dfloat, ne00,
+                                ne00, 1, sizeof(float), 0, 0,
+                                ne00, 1, sizeof(half),  0, 0, cudaStream_main);
+    }
+#else
+    dfloat * src1_dfloat = src1_ddf_i; // dfloat == float, no conversion
+#endif // GGML_CUDA_DMMV_F16
+
     switch (src0->type) {
         case GGML_TYPE_Q4_0:
-            dequantize_mul_mat_vec_q4_0_cuda(src0_ddq_i, src1_ddf_i, dst_ddf_i, ne00, nrows, cudaStream_main);
+            dequantize_mul_mat_vec_q4_0_cuda(src0_ddq_i, src1_dfloat, dst_ddf_i, ne00, nrows, cudaStream_main);
             break;
         case GGML_TYPE_Q4_1:
-            dequantize_mul_mat_vec_q4_1_cuda(src0_ddq_i, src1_ddf_i, dst_ddf_i, ne00, nrows, cudaStream_main);
+            dequantize_mul_mat_vec_q4_1_cuda(src0_ddq_i, src1_dfloat, dst_ddf_i, ne00, nrows, cudaStream_main);
             break;
         case GGML_TYPE_Q5_0:
-            dequantize_mul_mat_vec_q5_0_cuda(src0_ddq_i, src1_ddf_i, dst_ddf_i, ne00, nrows, cudaStream_main);
+            dequantize_mul_mat_vec_q5_0_cuda(src0_ddq_i, src1_dfloat, dst_ddf_i, ne00, nrows, cudaStream_main);
             break;
         case GGML_TYPE_Q5_1:
-            dequantize_mul_mat_vec_q5_1_cuda(src0_ddq_i, src1_ddf_i, dst_ddf_i, ne00, nrows, cudaStream_main);
+            dequantize_mul_mat_vec_q5_1_cuda(src0_ddq_i, src1_dfloat, dst_ddf_i, ne00, nrows, cudaStream_main);
             break;
         case GGML_TYPE_Q8_0:
-            dequantize_mul_mat_vec_q8_0_cuda(src0_ddq_i, src1_ddf_i, dst_ddf_i, ne00, nrows, cudaStream_main);
+            dequantize_mul_mat_vec_q8_0_cuda(src0_ddq_i, src1_dfloat, dst_ddf_i, ne00, nrows, cudaStream_main);
             break;
         case GGML_TYPE_Q2_K:
             dequantize_mul_mat_vec_q2_K_cuda(src0_ddq_i, src1_ddf_i, dst_ddf_i, ne00, nrows, cudaStream_main);
@@ -1746,7 +1816,7 @@ inline void ggml_cuda_op_dequantize_mul_mat_vec(
             dequantize_mul_mat_vec_q6_K_cuda(src0_ddq_i, src1_ddf_i, dst_ddf_i, ne00, nrows, cudaStream_main);
             break;
         case GGML_TYPE_F16:
-            convert_mul_mat_vec_f16_cuda(src0_ddq_i, src1_ddf_i, dst_ddf_i, ne00, nrows, cudaStream_main);
+            convert_mul_mat_vec_f16_cuda(src0_ddq_i, src1_dfloat, dst_ddf_i, ne00, nrows, cudaStream_main);
             break;
         default:
             GGML_ASSERT(false);
@@ -1754,6 +1824,12 @@ inline void ggml_cuda_op_dequantize_mul_mat_vec(
     }
     CUDA_CHECK(cudaGetLastError());
 
+#ifdef GGML_CUDA_DMMV_F16
+    if (src1_convert_f16) {
+        ggml_cuda_pool_free(src1_dfloat, ash);
+    }
+#endif // GGML_CUDA_DMMV_F16
+
     (void) src1;
     (void) dst;
     (void) src0_ddf_i;