File size: 3,419 Bytes
be903e2
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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
## supported platform

* Y = known work
* ? = shall work, not confirmed
* / = not applied

|    |windows|linux|android|mac|ios|
|---|---|---|---|---|---|
|intel|Y|Y|?|?|/|
|amd|Y|Y|/|?|/|
|nvidia|Y|Y|?|/|/|
|qcom|/|/|Y|/|/|
|apple|/|/|/|?|Y|
|arm|/|?|?|/|/|

## enable vulkan compute support
```
$ sudo dnf install vulkan-devel
$ cmake -DNCNN_VULKAN=ON ..
```

## enable vulkan compute inference
```cpp
ncnn::Net net;
net.opt.use_vulkan_compute = 1;
```

## proper allocator usage
```cpp
ncnn::VkAllocator* blob_vkallocator = vkdev.acquire_blob_allocator();
ncnn::VkAllocator* staging_vkallocator = vkdev.acquire_blob_allocator();

net.opt.blob_vkallocator = blob_vkallocator;
net.opt.workspace_vkallocator = blob_vkallocator;
net.opt.staging_vkallocator = staging_vkallocator;

// ....

// after inference
vkdev.reclaim_blob_allocator(blob_vkallocator);
vkdev.reclaim_staging_allocator(staging_vkallocator);
```

## select gpu device
```cpp
// get gpu count
int gpu_count = ncnn::get_gpu_count();

// set specified vulkan device before loading param and model
net.set_vulkan_device(0); // use device-0
net.set_vulkan_device(1); // use device-1
```

## zero-copy on unified memory device
```cpp
ncnn::VkMat blob_gpu;
ncnn::Mat mapped = blob_gpu.mapped();

// use mapped.data directly
```

## hybrid cpu/gpu inference
```cpp
ncnn::Extractor ex_cpu = net.create_extractor();
ncnn::Extractor ex_gpu = net.create_extractor();
ex_cpu.set_vulkan_compute(false);
ex_gpu.set_vulkan_compute(true);

#pragma omp parallel sections
{
    #pragma omp section
    {
        ex_cpu.input();
        ex_cpu.extract();
    }
    #pragma omp section
    {
        ex_gpu.input();
        ex_gpu.extract();
    }
}
```

## zero-copy gpu inference chaining
```cpp
ncnn::Extractor ex1 = net1.create_extractor();
ncnn::Extractor ex2 = net2.create_extractor();

ncnn::VkCompute cmd(&vkdev);

ncnn::VkMat conv1;
ncnn::VkMat conv2;
ncnn::VkMat conv3;

ex1.input("conv1", conv1);
ex1.extract("conv2", conv2, cmd);

ex2.input("conv2", conv2);
ex2.extract("conv3", conv3, cmd);

cmd.submit();

cmd.wait();

```

## batch inference
```cpp
int max_batch_size = vkdev->info.compute_queue_count;

ncnn::Mat inputs[1000];
ncnn::Mat outputs[1000];

#pragma omp parallel for num_threads(max_batch_size)
for (int i=0; i<1000; i++)
{
    ncnn::Extractor ex = net1.create_extractor();
    ex.input("data", inputs[i]);
    ex.extract("prob", outputs[i]);
}
```

## control storage and arithmetic precision

disable all lower-precision optimizations, get full fp32 precision

```cpp
ncnn::Net net;
net.opt.use_fp16_packed = false;
net.opt.use_fp16_storage = false;
net.opt.use_fp16_arithmetic = false;
net.opt.use_int8_storage = false;
net.opt.use_int8_arithmetic = false;
```

## debugging tips
```cpp
#define ENABLE_VALIDATION_LAYER 1 // modify to 1 in gpu.cpp
```

## add vulkan compute support to layer
1. add vulkan shader in src/layer/shader/

2. upload model weight data in Layer::upload_model()

3. setup pipeline in Layer::create_pipeline()

4. destroy pipeline in Layer::destroy_pipeline()

5. record command in Layer::forward()

## add optimized shader path
1. add vulkan shader in src/layer/shader/ named XXX_abc.comp

2. create pipeline with "XXX_abc"

3. record command using XXX_abc pipeline

## low-level op api
1. create layer

2. load param and load model

3. upload model

4. create pipeline

5. new command

6. record

7. submit and wait