llama.cpp/ggml/src/ggml-sycl/dmmv.cpp

#include "convert.hpp"
#include "dmmv.hpp"
#include "dequantize.hpp"
#include "presets.hpp"


static void convert_f16(const void * vx, const int ib, const int iqs, dfloat2 & v){
    const sycl::half *x = (const sycl::half *)vx;

    // automatic half -> float type cast if dfloat == float
    v.x() = x[ib + iqs + 0];
    v.y() = x[ib + iqs + 1];
}

static void convert_f32(const void * vx, const int ib, const int iqs, dfloat2 & v){
    const float * x = (const float *) vx;

    // 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>
static void dequantize_mul_mat_vec(const void * __restrict__ vx, const dfloat * __restrict__ y, float * __restrict__ dst, const int ncols, const int nrows,
                                   const sycl::nd_item<3> &item_ct1) {
    // qk = quantized weights per x block
    // qr = number of quantized weights per data value in x block
    const int row = item_ct1.get_group(2) * item_ct1.get_local_range(1) +
                    item_ct1.get_local_id(1);

    if (row >= nrows) {
        return;
    }

    const int tid = item_ct1.get_local_id(2);

    const int iter_stride = 2*GGML_SYCL_DMMV_X;
    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;

// partial sum for each thread
#ifdef GGML_SYCL_F16
    sycl::half2 tmp = {0.0f, 0.0f}; // two sums for f16 to take advantage of half2 intrinsics
#else
    float tmp = 0.0f;
#endif // GGML_SYCL_F16

    for (int i = 0; i < ncols; i += iter_stride) {
        const int col = i + vals_per_iter*tid;
        const int ib = (row*ncols + col)/qk; // x block index
        const int iqs = (col%qk)/qr; // x quant index
        const int iybs = col - col%qk; // y block start index

// processing >2 values per i iter is faster for fast GPUs
#pragma unroll
        for (int j = 0; j < vals_per_iter; j += 2) {
            // process 2 vals per j iter

            // dequantize
            // 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
            // for qr = 2 the y index needs to increase by 1 per j iter because of y_offset = qk/2
#ifdef GGML_SYCL_F16
            dfloat2 t1{y[iybs + iqs + j / qr + 0],
                        y[iybs + iqs + j / qr + y_offset]};

            tmp += v * t1;
#else
            tmp += v.x() * y[iybs + iqs + j / qr + 0];
            tmp += v.y() * y[iybs + iqs + j / qr + y_offset];
#endif // GGML_SYCL_F16
        }
    }

    // sum up partial sums and write back result
#pragma unroll
    for (int mask = WARP_SIZE / 2; mask > 0; mask >>= 1) {
        tmp +=
            dpct::permute_sub_group_by_xor(item_ct1.get_sub_group(), tmp, mask);
    }

    if (tid == 0) {
#ifdef GGML_SYCL_F16
        dst[row] = tmp.x() + tmp.y();
#else
        dst[row] = tmp;
#endif // GGML_SYCL_F16
    }
}

static void convert_mul_mat_vec_f16_sycl(const void *vx, const dfloat *y,
                                         float *dst, const int ncols,
                                         const int nrows,
                                         dpct::queue_ptr stream) {
    GGML_ASSERT(ncols % GGML_SYCL_DMMV_X == 0);
    const int block_num_y = (nrows + GGML_SYCL_MMV_Y - 1) / GGML_SYCL_MMV_Y;
    const sycl::range<3> block_nums(1, 1, block_num_y);
    const sycl::range<3> block_dims(1, GGML_SYCL_MMV_Y, WARP_SIZE);
    {
        dpct::has_capability_or_fail(stream->get_device(),
                                     {sycl::aspect::fp16});

        stream->parallel_for(
            sycl::nd_range<3>(block_nums * block_dims, block_dims),
            [=](sycl::nd_item<3> item_ct1) [[intel::reqd_sub_group_size(WARP_SIZE)]] {
                dequantize_mul_mat_vec<1, 1, convert_f16>(vx, y, dst, ncols,
                                                          nrows, item_ct1);
            });
    }
}

/*
DPCT1110:4: The total declared local variable size in device function
dequantize_mul_mat_vec_q2_k exceeds 128 bytes and may cause high register
pressure. Consult with your hardware vendor to find the total register size
available and adjust the code, or use smaller sub-group size to avoid high
register pressure.
*/
static void dequantize_mul_mat_vec_q2_k(const void *__restrict__ vx,
                                        const float *__restrict__ yy,
                                        float *__restrict__ dst,
                                        const int ncols, int nrows,
                                        const sycl::nd_item<3> &item_ct1) {

    static_assert(16%K_QUANTS_PER_ITERATION == 0, "16 must be divisible by K_QUANTS_PER_ITERATION");

    const int row = item_ct1.get_group(2) * item_ct1.get_local_range(1) +
                    item_ct1.get_local_id(1);
    if (row > nrows) return;

    const int num_blocks_per_row = ncols / QK_K;
    const int ib0 = row*num_blocks_per_row;

    const block_q2_K * x = (const block_q2_K *)vx + ib0;

    float tmp = 0; // partial sum for thread in warp

#if QK_K == 256
    const int tid =
        item_ct1.get_local_id(2) / K_QUANTS_PER_ITERATION; // 0...31 or 0...15
    const int ix =
        item_ct1.get_local_id(2) % K_QUANTS_PER_ITERATION; // 0 or 0,1

    const int step = 16/K_QUANTS_PER_ITERATION;

    const int im = tid/step;                             // 0 or 1. 0 computes 0..., 1 computes 128...
    const int in = tid - step*im;                        // 0...15 or 0...7

    const int l0 = K_QUANTS_PER_ITERATION*in;            // 0...15 or 0...14 in steps of 2
    const int q_offset = 32*im + l0;
    const int s_offset = 8*im;
    const int y_offset = 128*im + l0;

    uint32_t aux[4];
    const uint8_t * d = (const uint8_t *)aux;
    const uint8_t * m = (const uint8_t *)(aux + 2);

    for (int i = ix; i < num_blocks_per_row; i += K_QUANTS_PER_ITERATION) {

        const float   * y = yy + i * QK_K + y_offset;
        const uint8_t * q = x[i].qs + q_offset;

        const float dall = x[i].dm[0];
        const float dmin = x[i].dm[1];

        const uint32_t * a = (const uint32_t *)(x[i].scales + s_offset);
        aux[0] = a[0] & 0x0f0f0f0f;
        aux[1] = a[1] & 0x0f0f0f0f;
        aux[2] = (a[0] >> 4) & 0x0f0f0f0f;
        aux[3] = (a[1] >> 4) & 0x0f0f0f0f;

        float sum1 = 0, sum2 = 0;
        for (int l = 0; l < K_QUANTS_PER_ITERATION; ++l) {
            sum1 += y[l+ 0] * d[0] * ((q[l+ 0] >> 0) & 3)
                  + y[l+32] * d[2] * ((q[l+ 0] >> 2) & 3)
                  + y[l+64] * d[4] * ((q[l+ 0] >> 4) & 3)
                  + y[l+96] * d[6] * ((q[l+ 0] >> 6) & 3)
                  + y[l+16] * d[1] * ((q[l+16] >> 0) & 3)
                  + y[l+48] * d[3] * ((q[l+16] >> 2) & 3)
                  + y[l+80] * d[5] * ((q[l+16] >> 4) & 3)
                  +y[l+112] * d[7] * ((q[l+16] >> 6) & 3);
            sum2 += y[l+ 0] * m[0] + y[l+32] * m[2] + y[l+64] * m[4] + y[ l+96] * m[6]
                  + y[l+16] * m[1] + y[l+48] * m[3] + y[l+80] * m[5] + y[l+112] * m[7];

        }
        tmp += dall * sum1 - dmin * sum2;

    }
#else
    const int tid = item_ct1.get_local_id(2) /
                    (2 * K_QUANTS_PER_ITERATION); // 0...15 or 0...7
    const int ix = item_ct1.get_local_id(2) %
                   (2 * K_QUANTS_PER_ITERATION); // 0....1 or 0...3
    const int offset = tid * K_QUANTS_PER_ITERATION;

    uint32_t uaux[2];
    const uint8_t * d = (const uint8_t *)uaux;


    for (int i = ix; i < num_blocks_per_row; i += 2*K_QUANTS_PER_ITERATION) {

        const float   * y = yy + i * QK_K + offset;
        const uint8_t * q = x[i].qs + offset;
        const uint32_t * s = (const uint32_t *)x[i].scales;

        uaux[0] = s[0] & 0x0f0f0f0f;
        uaux[1] = (s[0] >> 4) & 0x0f0f0f0f;

        const sycl::float2 dall =
            x[i].dm.convert<float, sycl::rounding_mode::automatic>();

        float sum1 = 0, sum2 = 0;
        for (int l = 0; l < K_QUANTS_PER_ITERATION; ++l) {
            const uint8_t ql = q[l];
            sum1 += y[l+ 0] * d[0] * ((ql >> 0) & 3)
                  + y[l+16] * d[1] * ((ql >> 2) & 3)
                  + y[l+32] * d[2] * ((ql >> 4) & 3)
                  + y[l+48] * d[3] * ((ql >> 6) & 3);
            sum2 += y[l+0] * d[4] + y[l+16] * d[5] + y[l+32] * d[6] + y[l+48] * d[7];
        }
        tmp += dall.x() * sum1 - dall.y() * sum2;
    }

#endif

    // sum up partial sums and write back result
#pragma unroll
    for (int mask = QK_WARP_SIZE / 2; mask > 0; mask >>= 1) {
        tmp +=
            dpct::permute_sub_group_by_xor(item_ct1.get_sub_group(), tmp, mask);
    }

    if (item_ct1.get_local_id(2) == 0) {
        dst[row] = tmp;
    }
}

/*
DPCT1110:5: The total declared local variable size in device function
dequantize_mul_mat_vec_q3_k exceeds 128 bytes and may cause high register
pressure. Consult with your hardware vendor to find the total register size
available and adjust the code, or use smaller sub-group size to avoid high
register pressure.
*/
static void dequantize_mul_mat_vec_q3_k(const void *__restrict__ vx,
                                        const float *__restrict__ yy,
                                        float *__restrict__ dst,
                                        const int ncols, int nrows,
                                        const sycl::nd_item<3> &item_ct1) {

    const int row = item_ct1.get_group(2) * item_ct1.get_local_range(1) +
                    item_ct1.get_local_id(1);
    if (row > nrows) return;

    const int num_blocks_per_row = ncols / QK_K;
    const int ib0 = row*num_blocks_per_row;

    const block_q3_K * x = (const block_q3_K *)vx + ib0;

    float tmp = 0; // partial sum for thread in warp

#if QK_K == 256

    const uint16_t kmask1 = 0x0303;
    const uint16_t kmask2 = 0x0f0f;

    const int tid =
        item_ct1.get_local_id(2) / K_QUANTS_PER_ITERATION; // 0...31 or 0...16
    const int ix =
        item_ct1.get_local_id(2) % K_QUANTS_PER_ITERATION; // 0 or 0,1

    const int n  = K_QUANTS_PER_ITERATION;               // iterations in the inner loop
    const int step = 16/K_QUANTS_PER_ITERATION;
    const int im = tid/step;                             // 0 or 1. 0 computes 0..., 1 computes 128...
    const int in = tid - step*im;                        // 0....15 or 0...7

    const uint8_t m = 1 << (4*im);

    const int l0 = n*in;                                 // 0...15 or 0...14 in steps of 2
    const int q_offset =  32*im + l0;
    const int y_offset = 128*im + l0;

    uint16_t utmp[4];
    const int8_t * s = (const int8_t *)utmp;

    const uint16_t s_shift = 4*im;

    for (int i = ix; i < num_blocks_per_row; i += K_QUANTS_PER_ITERATION) {

        const float   * y  = yy + i * QK_K + y_offset;
        const uint8_t * q = x[i].qs + q_offset;
        const uint8_t * h = x[i].hmask + l0;

        const uint16_t * a = (const uint16_t *)x[i].scales;
        utmp[0] = ((a[0] >> s_shift) & kmask2) | (((a[4] >> (s_shift + 0)) & kmask1) << 4);
        utmp[1] = ((a[1] >> s_shift) & kmask2) | (((a[5] >> (s_shift + 0)) & kmask1) << 4);
        utmp[2] = ((a[2] >> s_shift) & kmask2) | (((a[4] >> (s_shift + 2)) & kmask1) << 4);
        utmp[3] = ((a[3] >> s_shift) & kmask2) | (((a[5] >> (s_shift + 2)) & kmask1) << 4);

        const float d = x[i].d;

        float sum = 0;
        for (int l = 0; l < n; ++l) {
            sum += y[l+ 0] * (s[0] - 32) * (((q[l] >> 0) & 3) - (h[l] & (m << 0) ? 0 : 4))
                 + y[l+32] * (s[2] - 32) * (((q[l] >> 2) & 3) - (h[l] & (m << 1) ? 0 : 4))
                 + y[l+64] * (s[4] - 32) * (((q[l] >> 4) & 3) - (h[l] & (m << 2) ? 0 : 4))
                 + y[l+96] * (s[6] - 32) * (((q[l] >> 6) & 3) - (h[l] & (m << 3) ? 0 : 4));
            sum += y[l+16] * (s[1] - 32) * (((q[l+16] >> 0) & 3) - (h[l+16] & (m << 0) ? 0 : 4))
                 + y[l+48] * (s[3] - 32) * (((q[l+16] >> 2) & 3) - (h[l+16] & (m << 1) ? 0 : 4))
                 + y[l+80] * (s[5] - 32) * (((q[l+16] >> 4) & 3) - (h[l+16] & (m << 2) ? 0 : 4))
                + y[l+112] * (s[7] - 32) * (((q[l+16] >> 6) & 3) - (h[l+16] & (m << 3) ? 0 : 4));
        }
        tmp += d * sum;

    }
#else

    const int tid = item_ct1.get_local_id(2)/(2*K_QUANTS_PER_ITERATION);  // 0...15 or 0...7
    const int ix  = item_ct1.get_local_id(2)%(2*K_QUANTS_PER_ITERATION);  // 0....1 or 0...3
    const int offset = tid * K_QUANTS_PER_ITERATION;         // 0...15 or 0...14
    const int in = offset/8;                                 // 0 or 1
    const int im = offset%8;                                 // 0...7

    for (int i = ix; i < num_blocks_per_row; i += 2*K_QUANTS_PER_ITERATION) {

        const float   * y = yy + i * QK_K + offset;
        const uint8_t * q = x[i].qs + offset;
        const uint8_t * s = x[i].scales;

        const float dall = (float)x[i].d;

        float sum = 0;
        for (int l = 0; l < K_QUANTS_PER_ITERATION; ++l) {
            const uint8_t hl = x[i].hmask[im+l] >> in;
            const uint8_t ql = q[l];
            sum += y[l+ 0] * dall * ((s[0] & 0xF) - 8) * ((int8_t)((ql >> 0) & 3) - ((hl >> 0) & 1 ? 0 : 4))
                 + y[l+16] * dall * ((s[0] >>  4) - 8) * ((int8_t)((ql >> 2) & 3) - ((hl >> 2) & 1 ? 0 : 4))
                 + y[l+32] * dall * ((s[1] & 0xF) - 8) * ((int8_t)((ql >> 4) & 3) - ((hl >> 4) & 1 ? 0 : 4))
                 + y[l+48] * dall * ((s[1] >>  4) - 8) * ((int8_t)((ql >> 6) & 3) - ((hl >> 6) & 1 ? 0 : 4));
        }
        tmp += sum;
    }
#endif

    // sum up partial sums and write back result
#pragma unroll
    for (int mask = QK_WARP_SIZE / 2; mask > 0; mask >>= 1) {
        tmp +=
            dpct::permute_sub_group_by_xor(item_ct1.get_sub_group(), tmp, mask);
    }

    if (item_ct1.get_local_id(2) == 0) {
        dst[row] = tmp;
    }
}

/*
DPCT1110:6: The total declared local variable size in device function
dequantize_mul_mat_vec_q4_k exceeds 128 bytes and may cause high register
pressure. Consult with your hardware vendor to find the total register size
available and adjust the code, or use smaller sub-group size to avoid high
register pressure.
*/
static void dequantize_mul_mat_vec_q4_k(const void *__restrict__ vx,
                                        const float *__restrict__ yy,
                                        float *__restrict__ dst,
                                        const int ncols, int nrows,
                                        const sycl::nd_item<3> &item_ct1) {

    const int row = item_ct1.get_group(2) * item_ct1.get_local_range(1) +
                    item_ct1.get_local_id(1);
    if (row > nrows) return;
    const int num_blocks_per_row = ncols / QK_K;
    const int ib0 = row*num_blocks_per_row;

    const block_q4_K * x = (const block_q4_K *)vx + ib0;

#if QK_K == 256
    const uint16_t kmask1 = 0x3f3f;
    const uint16_t kmask2 = 0x0f0f;
    const uint16_t kmask3 = 0xc0c0;

    const int tid =
        item_ct1.get_local_id(2) / K_QUANTS_PER_ITERATION; // 0...31 or 0...16
    const int ix =
        item_ct1.get_local_id(2) % K_QUANTS_PER_ITERATION; // 0 or 0,1

    const int step = 8/K_QUANTS_PER_ITERATION;           // 8 or 4

    const int il  = tid/step;                            // 0...3
    const int ir  = tid - step*il;                       // 0...7 or 0...3
    const int n   = 2 * K_QUANTS_PER_ITERATION;          // 2 or 4

    const int im = il/2;  // 0 or 1. 0 computes 0,32 + 128,160, 1 computes 64,96 + 192,224
    const int in = il%2;

    const int l0 = n*(2*ir + in);
    const int q_offset = 32*im + l0;
    const int y_offset = 64*im + l0;

    uint16_t aux[4];
    const uint8_t * sc = (const uint8_t *)aux;

#if K_QUANTS_PER_ITERATION == 2
    uint32_t q32[4];
    const uint8_t * q4 = (const uint8_t *)q32;
#else
    uint16_t q16[4];
    const uint8_t * q4 = (const uint8_t *)q16;
#endif

    float tmp = 0; // partial sum for thread in warp

    for (int i = ix; i < num_blocks_per_row; i += K_QUANTS_PER_ITERATION) {

        const float   * y1 = yy + i*QK_K + y_offset;
        const float   * y2 = y1 + 128;

        const float dall = x[i].dm[0];
        const float dmin = x[i].dm[1];

        const uint16_t * a = (const uint16_t *)x[i].scales;
        aux[0] = a[im+0] & kmask1;
        aux[1] = a[im+2] & kmask1;
        aux[2] = ((a[im+4] >> 0) & kmask2) | ((a[im+0] & kmask3) >> 2);
        aux[3] = ((a[im+4] >> 4) & kmask2) | ((a[im+2] & kmask3) >> 2);

#if K_QUANTS_PER_ITERATION == 2
        const uint32_t * q1 = (const uint32_t *)(x[i].qs + q_offset);
        const uint32_t * q2 = q1 + 16;

        q32[0] = q1[0] & 0x0f0f0f0f;
        q32[1] = q1[0] & 0xf0f0f0f0;
        q32[2] = q2[0] & 0x0f0f0f0f;
        q32[3] = q2[0] & 0xf0f0f0f0;

        sycl::float4 s = {0.f, 0.f, 0.f, 0.f};
        float smin = 0;
        for (int l = 0; l < 4; ++l) {
            s.x() += y1[l] * q4[l + 0]; s.y() += y1[l + 32] * q4[l + 4];
            s.z() += y2[l] * q4[l + 8]; s.w() += y2[l + 32] * q4[l + 12];
            smin += y1[l] * sc[2] + y1[l+32] * sc[3] + y2[l] * sc[6] + y2[l+32] * sc[7];
        }
        tmp += dall * (s.x() * sc[0] + s.y() * sc[1] * 1.f / 16.f +
                       s.z() * sc[4] + s.w() * sc[5] * 1.f / 16.f) -
               dmin * smin;
#else
        const uint16_t * q1 = (const uint16_t *)(x[i].qs + q_offset);
        const uint16_t * q2 = q1 + 32;

        q16[0] = q1[0] & 0x0f0f;
        q16[1] = q1[0] & 0xf0f0;
        q16[2] = q2[0] & 0x0f0f;
        q16[3] = q2[0] & 0xf0f0;

        float4 s = {0.f, 0.f, 0.f, 0.f};
        float smin = 0;
        for (int l = 0; l < 2; ++l) {
            s.x += y1[l] * q4[l+0]; s.y += y1[l+32] * q4[l+2];
            s.z += y2[l] * q4[l+4]; s.w += y2[l+32] * q4[l+6];
            smin += y1[l] * sc[2] + y1[l+32] * sc[3] + y2[l] * sc[6] + y2[l+32] * sc[7];
        }
        tmp += dall * (s.x * sc[0] + s.y * sc[1] * 1.f/16.f + s.z * sc[4] + s.w * sc[5] * 1.f/16.f) - dmin * smin;
#endif

    }
#else
    const int tid = item_ct1.get_local_id(2)/(2*K_QUANTS_PER_ITERATION);  // 0...15
    const int ix  = item_ct1.get_local_id(2)%(2*K_QUANTS_PER_ITERATION);

    const int step = tid * K_QUANTS_PER_ITERATION;

    uint16_t aux16[2];
    const uint8_t * s = (const uint8_t *)aux16;

    float tmp = 0;

    for (int i = ix; i < num_blocks_per_row; i += 2*K_QUANTS_PER_ITERATION) {
        const uint8_t * q = x[i].qs + step;
        const float   * y = yy + i*QK_K + step;
        const uint16_t * a = (const uint16_t *)x[i].scales;
        aux16[0] = a[0] & 0x0f0f;
        aux16[1] = (a[0] >> 4) & 0x0f0f;
        const float d = (float)x[i].dm[0];
        const float m = (float)x[i].dm[1];
        float sum = 0.f;
        for (int j = 0; j < K_QUANTS_PER_ITERATION; ++j) {
            sum += y[j+ 0] * (d * s[0] * (q[j+ 0] & 0xF) - m * s[2])
                 + y[j+16] * (d * s[0] * (q[j+16] & 0xF) - m * s[2])
                 + y[j+32] * (d * s[1] * (q[j+ 0] >>  4) - m * s[3])
                 + y[j+48] * (d * s[1] * (q[j+16] >>  4) - m * s[3]);
        }
        tmp += sum;
    }

#endif

    // sum up partial sums and write back result
#pragma unroll
    for (int mask = QK_WARP_SIZE / 2; mask > 0; mask >>= 1) {
        tmp +=
            dpct::permute_sub_group_by_xor(item_ct1.get_sub_group(), tmp, mask);
    }

    if (tid == 0) {
        dst[row] = tmp;
    }
}

/*
DPCT1110:7: The total declared local variable size in device function
dequantize_mul_mat_vec_q5_k exceeds 128 bytes and may cause high register
pressure. Consult with your hardware vendor to find the total register size
available and adjust the code, or use smaller sub-group size to avoid high
register pressure.
*/
static void dequantize_mul_mat_vec_q5_k(const void *__restrict__ vx,
                                        const float *__restrict__ yy,
                                        float *__restrict__ dst,
                                        const int ncols,
                                        const sycl::nd_item<3> &item_ct1) {

    const int row = item_ct1.get_group(2);
    const int num_blocks_per_row = ncols / QK_K;
    const int ib0 = row*num_blocks_per_row;

    const block_q5_K * x = (const block_q5_K *)vx + ib0;

    float tmp = 0; // partial sum for thread in warp

#if QK_K == 256
    const uint16_t kmask1 = 0x3f3f;
    const uint16_t kmask2 = 0x0f0f;
    const uint16_t kmask3 = 0xc0c0;

    const int tid = item_ct1.get_local_id(2) / 2; // 0...15
    const int ix = item_ct1.get_local_id(2) % 2;

    const int il  = tid/4;     // 0...3
    const int ir  = tid - 4*il;// 0...3
    const int n   = 2;

    const int im = il/2;  // 0 or 1. 0 computes 0,32 + 128,160, 1 computes 64,96 + 192,224
    const int in = il%2;

    const int l0 = n*(2*ir + in);
    const int q_offset = 32*im + l0;
    const int y_offset = 64*im + l0;

    const uint8_t hm1  = 1 << (2*im);
    const uint8_t hm2  = hm1 << 4;

    uint16_t aux[4];
    const uint8_t * sc = (const uint8_t *)aux;

    uint16_t q16[8];
    const uint8_t * q4 = (const uint8_t *)q16;

    for (int i = ix; i < num_blocks_per_row; i += 2) {

        const uint8_t * ql1 = x[i].qs + q_offset;
        const uint8_t * qh  = x[i].qh + l0;
        const float   * y1  = yy + i*QK_K + y_offset;
        const float   * y2  = y1 + 128;

        const float dall = x[i].dm[0];
        const float dmin = x[i].dm[1];

        const uint16_t * a = (const uint16_t *)x[i].scales;
        aux[0] = a[im+0] & kmask1;
        aux[1] = a[im+2] & kmask1;
        aux[2] = ((a[im+4] >> 0) & kmask2) | ((a[im+0] & kmask3) >> 2);
        aux[3] = ((a[im+4] >> 4) & kmask2) | ((a[im+2] & kmask3) >> 2);

        sycl::float4 sum = {0.f, 0.f, 0.f, 0.f};
        float smin = 0;
        const uint16_t * q1 = (const uint16_t *)ql1;
        const uint16_t * q2 = q1 + 32;
        q16[0] = q1[0] & 0x0f0f;
        q16[1] = q1[8] & 0x0f0f;
        q16[2] = (q1[0] >> 4) & 0x0f0f;
        q16[3] = (q1[8] >> 4) & 0x0f0f;
        q16[4] = q2[0] & 0x0f0f;
        q16[5] = q2[8] & 0x0f0f;
        q16[6] = (q2[0] >> 4) & 0x0f0f;
        q16[7] = (q2[8] >> 4) & 0x0f0f;
        for (int l = 0; l < n; ++l) {
            sum.x() +=
                y1[l + 0] * (q4[l + 0] + (qh[l + 0] & (hm1 << 0) ? 16 : 0)) +
                y1[l + 16] * (q4[l + 2] + (qh[l + 16] & (hm1 << 0) ? 16 : 0));
            sum.y() +=
                y1[l + 32] * (q4[l + 4] + (qh[l + 0] & (hm1 << 1) ? 16 : 0)) +
                y1[l + 48] * (q4[l + 6] + (qh[l + 16] & (hm1 << 1) ? 16 : 0));
            sum.z() +=
                y2[l + 0] * (q4[l + 8] + (qh[l + 0] & (hm2 << 0) ? 16 : 0)) +
                y2[l + 16] * (q4[l + 10] + (qh[l + 16] & (hm2 << 0) ? 16 : 0));
            sum.w() +=
                y2[l + 32] * (q4[l + 12] + (qh[l + 0] & (hm2 << 1) ? 16 : 0)) +
                y2[l + 48] * (q4[l + 14] + (qh[l + 16] & (hm2 << 1) ? 16 : 0));
            smin += (y1[l] + y1[l+16]) * sc[2] + (y1[l+32] + y1[l+48]) * sc[3]
                  + (y2[l] + y2[l+16]) * sc[6] + (y2[l+32] + y2[l+48]) * sc[7];
        }
        tmp += dall * (sum.x() * sc[0] + sum.y() * sc[1] + sum.z() * sc[4] +
                       sum.w() * sc[5]) -
               dmin * smin;
    }

#else
    const int tid = item_ct1.get_local_id(2)/(2*K_QUANTS_PER_ITERATION);  // 0...15
    const int ix  = item_ct1.get_local_id(2)%(2*K_QUANTS_PER_ITERATION);
    const int step = tid * K_QUANTS_PER_ITERATION;
    const int im = step/8;
    const int in = step%8;

    for (int i = ix; i < num_blocks_per_row; i += 2*K_QUANTS_PER_ITERATION) {
        const uint8_t * q = x[i].qs + step;
        const int8_t  * s = x[i].scales;
        const float   * y = yy + i*QK_K + step;
        const float     d = x[i].d;
        float sum = 0.f;
        for (int j = 0; j < K_QUANTS_PER_ITERATION; ++j) {
            const uint8_t h = x[i].qh[in+j] >> im;
            sum += y[j+ 0] * d * s[0] * ((q[j+ 0] & 0xF) - ((h >> 0) & 1 ? 0 : 16))
                 + y[j+16] * d * s[1] * ((q[j+16] & 0xF) - ((h >> 2) & 1 ? 0 : 16))
                 + y[j+32] * d * s[2] * ((q[j+ 0] >>  4) - ((h >> 4) & 1 ? 0 : 16))
                 + y[j+48] * d * s[3] * ((q[j+16] >>  4) - ((h >> 6) & 1 ? 0 : 16));
        }
        tmp += sum;
    }
#endif

    // sum up partial sums and write back result
#pragma unroll
    for (int mask = QK_WARP_SIZE / 2; mask > 0; mask >>= 1) {
        tmp +=
            dpct::permute_sub_group_by_xor(item_ct1.get_sub_group(), tmp, mask);
    }

    if (item_ct1.get_local_id(2) == 0) {
        dst[row] = tmp;
    }
}

static void dequantize_mul_mat_vec_q6_k(const void * __restrict__ vx, const float * __restrict__ yy, float * __restrict__ dst, const int ncols, int nrows,
                                        const sycl::nd_item<3> &item_ct1) {

    static_assert(16%K_QUANTS_PER_ITERATION == 0, "16 must be divisible by K_QUANTS_PER_ITERATION");

    const int row = item_ct1.get_group(2) * item_ct1.get_local_range(1) +
                    item_ct1.get_local_id(1);
    if (row > nrows) return;

    const int num_blocks_per_row = ncols / QK_K;
    const int ib0 = row*num_blocks_per_row;

    const block_q6_K * x = (const block_q6_K *)vx + ib0;

#if QK_K == 256

    const int tid =
        item_ct1.get_local_id(2) / K_QUANTS_PER_ITERATION; // 0...31 or 0...16
    const int ix =
        item_ct1.get_local_id(2) % K_QUANTS_PER_ITERATION; // 0 or 0, 1

    const int step = 16/K_QUANTS_PER_ITERATION;          // 16 or 8

    const int im = tid/step;                             // 0 or 1. 0 computes 0..., 1 computes 128...
    const int in = tid - step*im;                        // 0...15 or 0...7

#if K_QUANTS_PER_ITERATION == 1
    const int l0 = K_QUANTS_PER_ITERATION*in;            // 0...15
    const int is = 0;
#else
    const int l0 = 4 * in;                               // 0, 4, 8, ..., 28
    const int is = in / 4;
#endif
    const int ql_offset = 64*im + l0;
    const int qh_offset = 32*im + l0;
    const int s_offset  =  8*im + is;
    const int y_offset = 128*im + l0;

    float tmp = 0; // partial sum for thread in warp

    for (int i = ix; i < num_blocks_per_row; i += K_QUANTS_PER_ITERATION) {

        const float   * y  = yy + i * QK_K + y_offset;
        const uint8_t * ql = x[i].ql + ql_offset;
        const uint8_t * qh = x[i].qh + qh_offset;
        const int8_t  * s  = x[i].scales + s_offset;

        const float d = x[i].d;

#if K_QUANTS_PER_ITERATION == 1
        float sum = y[ 0] * s[0] * d * ((int8_t)((ql[ 0] & 0xF) | ((qh[ 0] & 0x03) << 4)) - 32)
                  + y[16] * s[1] * d * ((int8_t)((ql[16] & 0xF) | ((qh[16] & 0x03) << 4)) - 32)
                  + y[32] * s[2] * d * ((int8_t)((ql[32] & 0xF) | ((qh[ 0] & 0x0c) << 2)) - 32)
                  + y[48] * s[3] * d * ((int8_t)((ql[48] & 0xF) | ((qh[16] & 0x0c) << 2)) - 32)
                  + y[64] * s[4] * d * ((int8_t)((ql[ 0]  >> 4) | ((qh[ 0] & 0x30) >> 0)) - 32)
                  + y[80] * s[5] * d * ((int8_t)((ql[16]  >> 4) | ((qh[16] & 0x30) >> 0)) - 32)
                  + y[96] * s[6] * d * ((int8_t)((ql[32]  >> 4) | ((qh[ 0] & 0xc0) >> 2)) - 32)
                  +y[112] * s[7] * d * ((int8_t)((ql[48]  >> 4) | ((qh[16] & 0xc0) >> 2)) - 32);
        tmp += sum;
#else
        float sum = 0;
        for (int l = 0; l < 4; ++l) {
            sum += y[l+ 0] * s[0] * d * ((int8_t)((ql[l+ 0] & 0xF) | (((qh[l] >> 0) & 3) << 4)) - 32)
                 + y[l+32] * s[2] * d * ((int8_t)((ql[l+32] & 0xF) | (((qh[l] >> 2) & 3) << 4)) - 32)
                 + y[l+64] * s[4] * d * ((int8_t)((ql[l+ 0]  >> 4) | (((qh[l] >> 4) & 3) << 4)) - 32)
                 + y[l+96] * s[6] * d * ((int8_t)((ql[l+32]  >> 4) | (((qh[l] >> 6) & 3) << 4)) - 32);
        }
        tmp += sum;
#endif

    }

#else

    const int tid = item_ct1.get_local_id(2)/(2*K_QUANTS_PER_ITERATION);  // 0...7
    const int ix  = item_ct1.get_local_id(2)%(2*K_QUANTS_PER_ITERATION);  // 0...3

    const int step = tid * K_QUANTS_PER_ITERATION;

    float tmp = 0; // partial sum for thread in warp

    for (int i = ix; i < num_blocks_per_row; i += 2*K_QUANTS_PER_ITERATION) {

        const float   * y  = yy + i * QK_K + step;
        const uint8_t * ql = x[i].ql + step;
        const uint8_t * qh = x[i].qh + step;
        const int8_t  * s  = x[i].scales;

        const float d = x[i+0].d;

        float sum = 0;
        for (int j = 0; j < K_QUANTS_PER_ITERATION; ++j) {
            sum += y[j+ 0] * s[0] * d * ((int8_t)((ql[j+ 0] & 0xF) | ((qh[j] & 0x03) << 4)) - 32)
                 + y[j+16] * s[1] * d * ((int8_t)((ql[j+16] & 0xF) | ((qh[j] & 0x0c) << 2)) - 32)
                 + y[j+32] * s[2] * d * ((int8_t)((ql[j+ 0] >>  4) | ((qh[j] & 0x30) >> 0)) - 32)
                 + y[j+48] * s[3] * d * ((int8_t)((ql[j+16] >>  4) | ((qh[j] & 0xc0) >> 2)) - 32);
        }
        tmp += sum;

    }

#endif

    // sum up partial sums and write back result
#pragma unroll
    for (int mask = QK_WARP_SIZE / 2; mask > 0; mask >>= 1) {
        tmp +=
            dpct::permute_sub_group_by_xor(item_ct1.get_sub_group(), tmp, mask);
    }

    if (tid == 0) {
        dst[row] = tmp;
    }
}


static void dequantize_mul_mat_vec_q4_0_sycl(const void *vx, const dfloat *y,
                                             float *dst, const int ncols,
                                             const int nrows,
                                             dpct::queue_ptr stream) {
    GGML_ASSERT(ncols % GGML_SYCL_DMMV_X == 0);
    const int block_num_y = (nrows + GGML_SYCL_MMV_Y - 1) / GGML_SYCL_MMV_Y;
    // the number of rows may exceed maximum grid size in the y or z dimensions, use the x dimension instead
    const sycl::range<3> block_nums(1, 1, block_num_y);
    const sycl::range<3> block_dims(1, GGML_SYCL_MMV_Y, WARP_SIZE);
    {
        dpct::has_capability_or_fail(stream->get_device(),
                                     {sycl::aspect::fp16});

        stream->parallel_for(
            sycl::nd_range<3>(block_nums * block_dims, block_dims),
            [=](sycl::nd_item<3> item_ct1) [[intel::reqd_sub_group_size(WARP_SIZE)]] {
                dequantize_mul_mat_vec<QK4_0, QR4_0, dequantize_q4_0>(
                    vx, y, dst, ncols, nrows, item_ct1);
            });
    }
}

static void dequantize_mul_mat_vec_q4_1_sycl(const void *vx, const dfloat *y,
                                             float *dst, const int ncols,
                                             const int nrows,
                                             dpct::queue_ptr stream) {
    GGML_ASSERT(ncols % GGML_SYCL_DMMV_X == 0);
    const int block_num_y = (nrows + GGML_SYCL_MMV_Y - 1) / GGML_SYCL_MMV_Y;
    const sycl::range<3> block_nums(1, 1, block_num_y);
    const sycl::range<3> block_dims(1, GGML_SYCL_MMV_Y, WARP_SIZE);
    {
        dpct::has_capability_or_fail(stream->get_device(),
                                     {sycl::aspect::fp16});

        stream->parallel_for(
            sycl::nd_range<3>(block_nums * block_dims, block_dims),
            [=](sycl::nd_item<3> item_ct1) [[intel::reqd_sub_group_size(WARP_SIZE)]] {
                dequantize_mul_mat_vec<QK4_1, QR4_1, dequantize_q4_1>(
                    vx, y, dst, ncols, nrows, item_ct1);
            });
    }
}

static void dequantize_mul_mat_vec_q5_0_sycl(const void *vx, const dfloat *y,
                                             float *dst, const int ncols,
                                             const int nrows,
                                             dpct::queue_ptr stream) {
    GGML_ASSERT(ncols % GGML_SYCL_DMMV_X == 0);
    const int block_num_y = (nrows + GGML_SYCL_MMV_Y - 1) / GGML_SYCL_MMV_Y;
    const sycl::range<3> block_nums(1, 1, block_num_y);
    const sycl::range<3> block_dims(1, GGML_SYCL_MMV_Y, WARP_SIZE);
    {
        dpct::has_capability_or_fail(stream->get_device(),
                                     {sycl::aspect::fp16});

        stream->parallel_for(
            sycl::nd_range<3>(block_nums * block_dims, block_dims),
            [=](sycl::nd_item<3> item_ct1) [[intel::reqd_sub_group_size(WARP_SIZE)]] {
                dequantize_mul_mat_vec<QK5_0, QR5_0, dequantize_q5_0>(
                    vx, y, dst, ncols, nrows, item_ct1);
            });
    }
}

static void dequantize_mul_mat_vec_q5_1_sycl(const void *vx, const dfloat *y,
                                             float *dst, const int ncols,
                                             const int nrows,
                                             dpct::queue_ptr stream) {
    GGML_ASSERT(ncols % GGML_SYCL_DMMV_X == 0);
    const int block_num_y = (nrows + GGML_SYCL_MMV_Y - 1) / GGML_SYCL_MMV_Y;
    const sycl::range<3> block_nums(1, 1, block_num_y);
    const sycl::range<3> block_dims(1, GGML_SYCL_MMV_Y, WARP_SIZE);
    {
        dpct::has_capability_or_fail(stream->get_device(),
                                     {sycl::aspect::fp16});

        stream->parallel_for(
            sycl::nd_range<3>(block_nums * block_dims, block_dims),
            [=](sycl::nd_item<3> item_ct1) [[intel::reqd_sub_group_size(WARP_SIZE)]] {
                dequantize_mul_mat_vec<QK5_1, QR5_1, dequantize_q5_1>(
                    vx, y, dst, ncols, nrows, item_ct1);
            });
    }
}

static void dequantize_mul_mat_vec_q8_0_sycl(const void *vx, const dfloat *y,
                                             float *dst, const int ncols,
                                             const int nrows,
                                             dpct::queue_ptr stream) {
    GGML_ASSERT(ncols % GGML_SYCL_DMMV_X == 0);
    const int block_num_y = (nrows + GGML_SYCL_MMV_Y - 1) / GGML_SYCL_MMV_Y;
    const sycl::range<3> block_nums(1, 1, block_num_y);
    const sycl::range<3> block_dims(1, GGML_SYCL_MMV_Y, WARP_SIZE);
    {
        dpct::has_capability_or_fail(stream->get_device(),
                                     {sycl::aspect::fp16});

        stream->parallel_for(
            sycl::nd_range<3>(block_nums * block_dims, block_dims),
            [=](sycl::nd_item<3> item_ct1) [[intel::reqd_sub_group_size(WARP_SIZE)]] {
                dequantize_mul_mat_vec<QK8_0, QR8_0, dequantize_q8_0>(
                    vx, y, dst, ncols, nrows, item_ct1);
            });
    }
}

static void dequantize_mul_mat_vec_q2_K_sycl(const void *vx, const float *y,
                                             float *dst, const int ncols,
                                             const int nrows,
                                             dpct::queue_ptr stream) {
    GGML_ASSERT(ncols % QK_K == 0);
    const int ny = 2; // very slightly faster than 1 even when K_QUANTS_PER_ITERATION = 2
    const int block_num_y = (nrows + ny - 1) / ny;
    const sycl::range<3> block_nums(1, 1, block_num_y);
    const sycl::range<3> block_dims(1, ny, QK_WARP_SIZE);
    stream->parallel_for(
        sycl::nd_range<3>(block_nums * block_dims, block_dims),
        [=](sycl::nd_item<3> item_ct1) [[intel::reqd_sub_group_size(QK_WARP_SIZE)]] {
            dequantize_mul_mat_vec_q2_k(vx, y, dst, ncols, nrows, item_ct1);
        });
}

static void dequantize_mul_mat_vec_q3_K_sycl(const void *vx, const float *y,
                                             float *dst, const int ncols,
                                             const int nrows,
                                             dpct::queue_ptr stream) {
    GGML_ASSERT(ncols % QK_K == 0);
    const int ny = 2 / K_QUANTS_PER_ITERATION;
    const int block_num_y = (nrows + ny - 1) / ny;
    const sycl::range<3> block_nums(1, 1, block_num_y);
    const sycl::range<3> block_dims(1, ny, QK_WARP_SIZE);
    stream->parallel_for(
        sycl::nd_range<3>(block_nums * block_dims, block_dims),
        [=](sycl::nd_item<3> item_ct1) [[intel::reqd_sub_group_size(QK_WARP_SIZE)]] {
            dequantize_mul_mat_vec_q3_k(vx, y, dst, ncols, nrows, item_ct1);
        });
}

static void dequantize_mul_mat_vec_q4_K_sycl(const void *vx, const float *y,
                                             float *dst, const int ncols,
                                             const int nrows,
                                             dpct::queue_ptr stream) {
    GGML_ASSERT(ncols % QK_K == 0);
    const int ny = 2 / K_QUANTS_PER_ITERATION;
    const int block_num_y = (nrows + ny - 1) / ny;
    const sycl::range<3> block_nums(1, 1, block_num_y);
    const sycl::range<3> block_dims(1, ny, QK_WARP_SIZE);
    stream->parallel_for(
        sycl::nd_range<3>(block_nums * block_dims, block_dims),
        [=](sycl::nd_item<3> item_ct1) [[intel::reqd_sub_group_size(QK_WARP_SIZE)]] {
            dequantize_mul_mat_vec_q4_k(vx, y, dst, ncols, nrows, item_ct1);
        });
}

static void dequantize_mul_mat_vec_q5_K_sycl(const void *vx, const float *y,
                                             float *dst, const int ncols,
                                             const int nrows,
                                             dpct::queue_ptr stream) {
    GGML_ASSERT(ncols % QK_K == 0);
    const sycl::range<3> block_dims(1, 1, QK_WARP_SIZE);
    stream->parallel_for(
        sycl::nd_range<3>(sycl::range<3>(1, 1, nrows) * block_dims, block_dims),
        [=](sycl::nd_item<3> item_ct1) [[intel::reqd_sub_group_size(QK_WARP_SIZE)]] {
            dequantize_mul_mat_vec_q5_k(vx, y, dst, ncols, item_ct1);
        });
}

static void dequantize_mul_mat_vec_q6_K_sycl(const void *vx, const float *y,
                                             float *dst, const int ncols,
                                             const int nrows,
                                             dpct::queue_ptr stream) {
    GGML_ASSERT(ncols % QK_K == 0);
    const int ny = 2 / K_QUANTS_PER_ITERATION;
    const int block_num_y = (nrows + ny - 1) / ny;
    const sycl::range<3> block_nums(1, 1, block_num_y);
    const sycl::range<3> block_dims(1, ny, QK_WARP_SIZE);
    stream->parallel_for(
        sycl::nd_range<3>(block_nums * block_dims, block_dims),
        [=](sycl::nd_item<3> item_ct1) [[intel::reqd_sub_group_size(QK_WARP_SIZE)]] {
            dequantize_mul_mat_vec_q6_k(vx, y, dst, ncols, nrows, item_ct1);
        });
}

void ggml_sycl_op_dequantize_mul_mat_vec(
    ggml_backend_sycl_context & ctx,
    const ggml_tensor *src0, const ggml_tensor *src1, ggml_tensor *dst,
    const char *src0_dd_i, const float *src1_ddf_i, const char *src1_ddq_i,
    float *dst_dd_i, const int64_t row_low, const int64_t row_high,
    const int64_t src1_ncols, const int64_t src1_padded_row_size,
    const dpct::queue_ptr &stream) {

    const int64_t ne00 = src0->ne[0];
    const int64_t row_diff = row_high - row_low;

    GGML_ASSERT(src1->type == GGML_TYPE_F32);
    // on some GPUs it is faster to convert src1 to half and to use half precision intrinsics
#ifdef GGML_SYCL_F16
    ggml_sycl_pool_alloc<sycl::half> src1_dfloat_a(ctx.pool());
    sycl::half *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 = src1_dfloat_a.alloc(ne00);
        const to_fp16_sycl_t to_fp16_sycl = ggml_get_to_fp16_sycl(src1->type);
        GGML_ASSERT(to_fp16_sycl != nullptr);
        to_fp16_sycl(src1_ddf_i, src1_dfloat, ne00, stream);
    }
#else
    const dfloat * src1_dfloat = (const dfloat *) src1_ddf_i; // dfloat == float, no conversion
#endif // GGML_SYCL_F16

    switch (src0->type) {
        case GGML_TYPE_Q4_0:
            dequantize_mul_mat_vec_q4_0_sycl(src0_dd_i, src1_dfloat, dst_dd_i, ne00, row_diff, stream);
            break;
        case GGML_TYPE_Q4_1:
            dequantize_mul_mat_vec_q4_1_sycl(src0_dd_i, src1_dfloat, dst_dd_i, ne00, row_diff, stream);
            break;
        case GGML_TYPE_Q5_0:
            dequantize_mul_mat_vec_q5_0_sycl(src0_dd_i, src1_dfloat, dst_dd_i, ne00, row_diff, stream);
            break;
        case GGML_TYPE_Q5_1:
            dequantize_mul_mat_vec_q5_1_sycl(src0_dd_i, src1_dfloat, dst_dd_i, ne00, row_diff, stream);
            break;
        case GGML_TYPE_Q8_0:
            dequantize_mul_mat_vec_q8_0_sycl(src0_dd_i, src1_dfloat, dst_dd_i, ne00, row_diff, stream);
            break;
        case GGML_TYPE_Q2_K:
            dequantize_mul_mat_vec_q2_K_sycl(src0_dd_i, src1_ddf_i, dst_dd_i, ne00, row_diff, stream);
            break;
        case GGML_TYPE_Q3_K:
            dequantize_mul_mat_vec_q3_K_sycl(src0_dd_i, src1_ddf_i, dst_dd_i, ne00, row_diff, stream);
            break;
        case GGML_TYPE_Q4_K:
            dequantize_mul_mat_vec_q4_K_sycl(src0_dd_i, src1_ddf_i, dst_dd_i, ne00, row_diff, stream);
            break;
        case GGML_TYPE_Q5_K:
            dequantize_mul_mat_vec_q5_K_sycl(src0_dd_i, src1_ddf_i, dst_dd_i, ne00, row_diff, stream);
            break;
        case GGML_TYPE_Q6_K:
            dequantize_mul_mat_vec_q6_K_sycl(src0_dd_i, src1_ddf_i, dst_dd_i, ne00, row_diff, stream);
            break;
        case GGML_TYPE_F16:
            convert_mul_mat_vec_f16_sycl(src0_dd_i, src1_dfloat, dst_dd_i, ne00, row_diff, stream);
            break;
        default:
            printf("ggml_sycl_op_dequantize_mul_mat_vec unsupported GGML_TYPE %d\n", src0->type);
            GGML_ASSERT(false);
            break;
    }

    (void) src1;
    (void) dst;
    (void) src1_ddq_i;
    (void) src1_ncols;
    (void) src1_padded_row_size;
}