File size: 6,596 Bytes
4a28d4d
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
// Copyright (c) OpenMMLab. All rights reserved.

#pragma once

#include "src/turbomind/kernels/attention/quantization.h"
#include "src/turbomind/kernels/core/array_ops.h"
#include "src/turbomind/kernels/core/common.h"
#include "src/turbomind/kernels/core/math.h"
#include "src/turbomind/kernels/gemm/test/test_utils.h"
#include "src/turbomind/kernels/gemm/types.h"

#include <thrust/execution_policy.h>
#include <thrust/universal_vector.h>

namespace turbomind::gemm {

// quantize using `scale` and `zeros`,
template<class T>
__global__ void find_stats(Array<T, 2>* minmax, const T* src, int N, int K, int G)
{
    int n_idx = blockIdx.x * blockDim.x + threadIdx.x;
    int k_idx = blockIdx.y;

    if (n_idx >= N || k_idx * G >= K) {
        return;
    }

    float minval = std::numeric_limits<float>::infinity();
    float maxval = -minval;

    const int L = min(K, G);

    for (int k = 0; k < L; k += 8) {
        Array<T, 8> vec;
        Load(vec, &src[n_idx * K + k_idx * G + k]);
        PRAGMA_UNROLL
        for (int i = 0; i < vec.size(); ++i) {
            minval = __hmin(minval, vec[i]);
            maxval = __hmax(maxval, vec[i]);
        }
    }

    // store in n-major
    Store(minmax[k_idx * N + n_idx].data(), Array<T, 2>{minval, maxval});
}

template<class Q, bool asym, class T>
__global__ void find_params(T* param, const Array<T, 2>* minmax, int count)
{
    int global_idx = threadIdx.x + blockIdx.x * blockDim.x;
    if (global_idx >= count) {
        return;
    }
    auto        stats     = minmax[global_idx];
    const float inv_q_max = fdividef(1.f, (1 << bitsof<Q>)-1);

    static_assert(asym);

    float scale = (T)(((float)stats[1] - (float)stats[0]) * inv_q_max);

    // force trivial scale / zero for debugging
    if constexpr (0) {
        stats[0] = 0;
        scale    = 1.f;
    }

    Store(param + global_idx * 2, Array<T, 2>{scale, stats[0]});
}

template<class Q, class T>
__global__ void quantize(uint16_t* dst, T* pseudo, const T* src, const T* stats, int N, int K, int G)
{
    static_assert(bitsof<Q> <= 16);
    static_assert(bitsof<T> == 16);  // fp16 & bf16

    int n_idx = blockIdx.x * blockDim.x + threadIdx.x;
    int k_idx = blockIdx.y;

    if (n_idx >= N || k_idx * G >= K) {
        return;
    }

    Array<T, 2> param;
    Load(param, stats + (k_idx * N + n_idx) * 2);

    float inv_scale = fdividef(1.f, param[0]);

    const int L = min(K, G);

    for (int k = 0; k < L; k += 8) {
        Array<T, 8>        vi;
        Array<uint16_t, 8> vo;
        Load(vi, &src[n_idx * K + k_idx * G + k]);

        PRAGMA_UNROLL
        for (int i = 0; i < 8; ++i) {
            float u = (static_cast<float>(vi[i] - param[1])) * inv_scale;
            vo[i]   = quant<uint16_t>(u, bitsof<Q>);
        }
        Store(&dst[n_idx * K + k_idx * G + k], vo);

        if (pseudo) {
            Array<T, 8> vf;
            PRAGMA_UNROLL
            for (int i = 0; i < 8; ++i) {
                vf[i] = __hfma(static_cast<T>(vo[i]), param[0], param[1]);
            }
            Store(&pseudo[n_idx * K + k_idx * G + k], vf);
        }
    }
}

template<class T>
__global__ void transpose(const T* src, T* dst, int s, int c)
{
    const int cid = threadIdx.x + blockIdx.x * blockDim.x;
    const int sid = threadIdx.y + blockIdx.y * blockDim.y;
    if (sid < s && cid < c) {
        dst[cid * s + sid] = src[sid * c + cid];
    }
}

template<class T>
void invokeTranspose(const T* src, T* dst, int s, int c, cudaStream_t stream)
{
    const dim3 block{32, 16};
    const dim3 grid(ceil_div<int>(c, block.x), ceil_div<int>(s, block.y));

    transpose<<<grid, block, 0, stream>>>(src, dst, s, c);
}

template<class D, class S>
void Quantize(const thrust::universal_vector<S>&  x,
              int                                 m,
              int                                 k,
              Order                               order,
              int                                 group_size,
              thrust::universal_vector<S>&        x_p,  // pseudo-quantized
              thrust::universal_vector<uint16_t>& x_q,  // quantized ushort
              thrust::universal_vector<S>&        x_u,  // scales & zeros (always m-major)
              cudaStream_t                        stream)

{
    auto policy = thrust::device.on(stream);

    thrust::universal_vector<S>           _x(x.size());
    thrust::universal_vector<S>           _x_p(x.size());
    thrust::universal_vector<uint16_t>    _x_q(x.size());
    thrust::universal_vector<Array<S, 2>> stats(ceil_div(k, group_size) * m);

    x_p.resize(x.size());
    x_q.resize(x.size());
    /// FIXME: correct the size
    x_u.resize(stats.size() * 2);

    if (order == Order::kRowMajor) {
        thrust::copy(policy, x.begin(), x.end(), _x.begin());
    }
    else {
        invokeTranspose(x.data().get(), _x.data().get(), k, m, stream);
    }

    const int  block = std::min(256, m);
    const dim3 grid(ceil_div(m, block), ceil_div(k, group_size));

    find_stats<<<grid, block, 0, stream>>>(stats.data().get(),  //
                                           _x.data().get(),
                                           m,
                                           k,
                                           group_size);

    find_params<D, true><<<ceil_div<int>(stats.size(), 256), 256, 0, stream>>>(  //
        x_u.data().get(),
        stats.data().get(),
        stats.size());

    quantize<D><<<grid, block, 0, stream>>>(_x_q.data().get(),  //
                                            _x_p.data().get(),
                                            _x.data().get(),
                                            x_u.data().get(),
                                            m,
                                            k,
                                            group_size);

    if (order == Order::kRowMajor) {
        thrust::copy(policy, _x_p.begin(), _x_p.end(), x_p.begin());
        thrust::copy(policy, _x_q.begin(), _x_q.end(), x_q.begin());
    }
    else {
        invokeTranspose(_x_p.data().get(), x_p.data().get(), m, k, stream);
        invokeTranspose(_x_q.data().get(), x_q.data().get(), m, k, stream);
    }

    cudaStreamSynchronize(stream);

    // Compare(_x_p.data().get(), _x.data().get(), k, k, m);

    const int kg = ceil_div(k, group_size);
    for (int i = 0; i < m * kg; ++i) {
        // int mi = i % m;
        // int ki = i / m;

        // x_u[i * 2]     = i;
        // x_u[i * 2 + 1] = i;

        // x_u[i * 2]     = i * 2;
        // x_u[i * 2 + 1] = i * 2 + 1;
    }
}

}  // namespace turbomind::gemm