File size: 11,836 Bytes
8a42f8f
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
import unittest

import torch
import torch.nn as nn
import torch.nn.functional as F
import torch.optim as optim

from apex import amp


from utils import common_init, FLOAT


class MyModel(torch.nn.Module):
    def __init__(self):
        super(MyModel, self).__init__()
        self.conv1 = nn.Conv2d(3, 6, 3, 1, 1)
        self.bn1 = nn.BatchNorm2d(6)
        self.param = nn.Parameter(torch.randn(1))

    def forward(self, x):
        x = x * self.param
        x = F.relu(self.conv1(x))
        x = self.bn1(x)
        return x


class TestCheckpointing(unittest.TestCase):
    def setUp(self):
        self.initial_lr = 1e-3
        self.test_opt_levels = ("O0", "O1", "O2", "O3")

    def seed(self):
        torch.manual_seed(2809)
        torch.backends.cudnn.benchmark = False
        torch.backends.cudnn.deterministic = True

    def check_state_dict_fp32(self, state_dict):
        for key in state_dict:
            if 'num_batches_tracked' in key:
                continue
            param = state_dict[key]
            self.assertEqual(param.type(), FLOAT,
                             'Parameter in state_dict not FLOAT')

    def train_step(self, model, optimizer, data, loss_ids):
        optimizer.zero_grad()        

        output = model(data)

        # Call backward for num_losses-1
        for idx in loss_ids:
            loss = output.mean()
            with amp.scale_loss(loss, optimizer, loss_id=idx) as scaled_loss:
                scaled_loss.backward(retain_graph=True)

        optimizer.step()
        return output

    def compare_models(self, modelA, modelB, test_setup=''):
        state_dictA = modelA.state_dict()
        state_dictB = modelB.state_dict()
        self.assertEqual(len(state_dictA), len(state_dictB),
                         'state_dicts have different lengths' + test_setup)
        for key in state_dictA:
            paramA = state_dictA[key]
            paramB = state_dictB[key]
            self.assertTrue((paramA==paramB).all(),
                msg='Parameters in state_dices not equal.' +
                    'key: {}\nparam: {}\nrestored: {}\ndiff: {} for {}'.format(
                        key, paramA, paramB, paramA - paramB, test_setup))

    def test_restoring(self):
        nb_epochs = 10
        nb_epochs_restore = nb_epochs // 2
        for opt_level in self.test_opt_levels:
            for res_opt_level in self.test_opt_levels:
                for amp_before_load in [True, False]:
                    for num_losses in range(1, 3):
                        test_setup = ('#' * 75 + '\n' + \
                              f'opt_level {opt_level}\n' + \
                              f'restore_opt_level {res_opt_level}\n' + \
                              f'amp_before_load {amp_before_load}\n' + \
                              f'num_losses {num_losses}\n')

                        self.seed()

                        # Create reference model
                        model = MyModel().to('cuda')

                        optimizer = optim.SGD(model.parameters(),
                                              lr=self.initial_lr)

                        # Initialize with num_losses*2 for the original model and the restored one
                        model, optimizer = amp.initialize(
                            model, optimizer, opt_level=opt_level,
                            num_losses=num_losses*2, verbosity=0)

                        # Compare training behavior for same restore option
                        # We cannot really generalize it, since a saved model in O0
                        # would introduce a skipped step in O1, which will raise an error
                        if opt_level == res_opt_level:
                            # train for nb_epochs and restore after nb_epochs_restore
                            for epoch in range(nb_epochs):
    
                                x = torch.randn(16, 3, 24, 24, device='cuda')
                                output = self.train_step(
                                    model, optimizer, x, range(num_losses))
                                # Initialize model one step before comparing.
                                # Otherwise the batchnorm layers will be updated 
                                # additionally in restore_model
                                if epoch == (nb_epochs_restore - 1):
                                    # Load model and optimizer
                                    checkpoint = {
                                        'model': model.state_dict(),
                                        'optimizer': optimizer.state_dict(),
                                        'amp': amp.state_dict()
                                    }
                                    # Check state_dict for FP32 tensors
                                    self.check_state_dict_fp32(checkpoint['model'])

                                    # Restore model
                                    restore_model = MyModel().to('cuda')
                                    restore_optimizer = optim.SGD(
                                        restore_model.parameters(),
                                        lr=self.initial_lr)

                                    if amp_before_load:
                                        restore_model, restore_optimizer = amp.initialize(
                                            restore_model,
                                            restore_optimizer,
                                            opt_level=res_opt_level,
                                            num_losses=num_losses*2,
                                            verbosity=0)

                                    restore_model.load_state_dict(checkpoint['model'])
                                    restore_optimizer.load_state_dict(checkpoint['optimizer'])
                                    # FIXME: We cannot test the amp.state_dict in the same script
                                    # amp.load_state_dict(checkpoint['amp'])

                                    if not amp_before_load:
                                        restore_model, restore_optimizer = amp.initialize(
                                            restore_model,
                                            restore_optimizer,
                                            opt_level=res_opt_level,
                                            num_losses=num_losses*2,
                                            verbosity=0)

                                elif epoch >= nb_epochs_restore:
                                    restore_output = self.train_step(
                                        restore_model,
                                        restore_optimizer,
                                        x,
                                        range(num_losses, num_losses*2))
                                    self.assertTrue(
                                        torch.allclose(output.float(), restore_output.float()),
                                        'Output of reference and restored models differ for ' + test_setup)
                                    self.compare_models(model, restore_model, test_setup)
                        # if opt_level != res_opt_level
                        else:
                            # skip tests for different opt_levels
                            continue

    def test_loss_scale_decrease(self):
        num_losses = 3
        nb_decrease_loss_scales = [0, 1, 2]
        for opt_level in self.test_opt_levels:
            #print('#' * 75 + f'\n opt_level {opt_level}\n')
            # Create new tmp copy for this run
            nb_decrease_loss_scales_tmp = list(nb_decrease_loss_scales)

            model = MyModel().to('cuda')
        
            optimizer = optim.SGD(model.parameters(),
                                  lr=self.initial_lr)
        
            model, optimizer = amp.initialize(
                model, optimizer, opt_level=opt_level, num_losses=num_losses,
                verbosity=0)

            if amp._amp_state.opt_properties.loss_scale != 'dynamic':
                #print('Static loss scale set. Skipping opt_level.')
                continue
        
            # force to skip some updates to decrease the loss_scale
            initial_loss_scales = []
            for idx in range(num_losses):
                initial_loss_scales.append(
                    amp._amp_state.loss_scalers[idx].loss_scale())
            
            for _ in range(len(nb_decrease_loss_scales)):
                x = torch.randn(16, 3, 24, 24, device='cuda')
                for idx in range(num_losses):
                    while nb_decrease_loss_scales_tmp[idx] > 0:
                        optimizer.zero_grad()
                        output = model(x * 2**17)
                        loss = output.mean()            
                    
                        with amp.scale_loss(loss, optimizer, loss_id=idx) as scaled_loss:
                            scaled_loss.backward(retain_graph=True)
                        optimizer.step()
                        nb_decrease_loss_scales_tmp[idx] -= 1
                
            # Check loss scales afterwards
            updated_loss_scales = []
            for idx in range(num_losses):
                updated_loss_scales.append(
                    amp._amp_state.loss_scalers[idx].loss_scale())
            for factor, update_ls, init_ls in zip(nb_decrease_loss_scales,
                                                  updated_loss_scales,
                                                  initial_loss_scales):
                self.assertEqual(update_ls, init_ls / 2**factor)

            # Check state dict
            amp_state_dict = amp.state_dict()
            for scaler_idx, factor, init_ls in zip(amp_state_dict,
                                                   nb_decrease_loss_scales,
                                                   initial_loss_scales):
                scaler = amp_state_dict[scaler_idx]
                self.assertEqual(scaler['loss_scale'], init_ls / 2**factor)
                unskipped_target = 0
                self.assertEqual(scaler['unskipped'], unskipped_target)

    def test_state_dict(self):
        for opt_level in self.test_opt_levels:
            # Skip O3
            if opt_level == 'O3':
                continue

            model = MyModel().to('cuda')
            optimizer = optim.Adam(model.parameters(), lr=1e-3)
            model, optimizer = amp.initialize(
                model, optimizer, opt_level=opt_level, verbosity=0)

            # Export state_dict and check for Half
            state_dict = model.state_dict()
            for key in state_dict:
                self.assertFalse('Half' in state_dict[key].type())

            # Check, if model is still trainable
            # Create dummy data
            data = torch.randn(10, 3, 4, 4, device='cuda')
            target = torch.randn(10, 6, 4, 4, device='cuda')
            
            # Get initnial loss
            optimizer.zero_grad()
            output = model(data)
            loss = F.mse_loss(output, target)
            with amp.scale_loss(loss, optimizer) as scaled_loss:
                scaled_loss.backward()
            optimizer.step()
            last_loss = loss.item()

            # train for some epochs
            for epoch in range(10):
                optimizer.zero_grad()
                output = model(data)
                loss = F.mse_loss(output, target)
                with amp.scale_loss(loss, optimizer) as scaled_loss:
                    scaled_loss.backward()
                optimizer.step()
                self.assertTrue(loss.item() < last_loss)
                last_loss = loss.item()

if __name__=='__main__':
    unittest.main()