File size: 10,589 Bytes
1571051
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
from .huggingface_utils import get_auth_token
from .onnx_models_structure import (
    T5Encoder,
    DecoderWithLMhead,
    DecoderWithLMheadInitial,
)
from transformers import (
    AutoConfig,
    T5ForConditionalGeneration,
    MT5ForConditionalGeneration,
)
import torch
import functools
import operator
from progress.bar import Bar
from pathlib import Path
import os

_folder = Path.cwd()
saved_models_path = _folder.joinpath("models")

Bar.check_tty = False


def create_t5_encoder_decoder(pretrained_version="t5-base"):
    """Generates an encoder and a decoder model with a language model head from a pretrained huggingface model

    Args:
        pretrained_version (str): Name of a pretrained model, or path to a pretrained / finetuned version of T5

    Returns:
        simplified_encoder: pytorch t5 encoder with a wrapper to output only the hidden states
        decoder_with_lm_head: pytorch t5 decoder with a language modeling head
    """

    if 'mt5' in pretrained_version:
        model = MT5ForConditionalGeneration.from_pretrained(pretrained_version, use_auth_token=get_auth_token())
    else:
        model = T5ForConditionalGeneration.from_pretrained(pretrained_version, use_auth_token=get_auth_token())

    return turn_model_into_encoder_decoder(model)


def turn_model_into_encoder_decoder(model):
    encoder = model.encoder
    decoder = model.decoder
    lm_head = model.lm_head

    decoder_with_lm_head = DecoderWithLMhead(decoder, lm_head, model.config)
    simplified_encoder = T5Encoder(encoder)
    decoder_with_lm_head_init = DecoderWithLMheadInitial(decoder, lm_head, model.config)

    return simplified_encoder, decoder_with_lm_head, decoder_with_lm_head_init


def generate_onnx_representation(
    pretrained_version=None,
    model=None,
    output_path=None,
    input_sequence_length=256,
    onnx_opset_version=12,  # no other opset versions are tested, change at your own risk
):
    """Exports a given huggingface pretrained model, or a given model and tokenizer, to onnx

    Args:
        pretrained_version (str): Name of a pretrained model, or path to a pretrained / finetuned version of T5
        output_path (Optional[str]): if missing then use ./models
        input_sequence_length (Optional[int]): typical input sequence length, for use by the ORT for possible optimization
        onnx_opset_version (Optional[int]): ONNX Operator Set Version, default 12 is the only tested version
    """
    if (pretrained_version is None) and model is None:
        print(
            "You need to specify pretrained_version (the pretrained model you wish to export). Alternatively you can export a model you have in memory."
        )
        return

    if model is not None:
        (
            simplified_encoder,
            decoder_with_lm_head,
            decoder_with_lm_head_init,
        ) = turn_model_into_encoder_decoder(model)
    else:
        (
            simplified_encoder,
            decoder_with_lm_head,
            decoder_with_lm_head_init,
        ) = create_t5_encoder_decoder(pretrained_version)

    # model paths for enc, dec and dec_init
    output_path = saved_models_path if output_path is None else Path(output_path)
    encoder_path, decoder_path, init_decoder_path = get_model_paths(
        pretrained_version, output_path, quantized=False
    )

    model_config = AutoConfig.from_pretrained(pretrained_version, use_auth_token=get_auth_token())

    # Though these are dummy inputs, ORT optimizations do reference these values,
    # so it is worth using values as close to production as possible
    batch_size = 1  # not configurable since only CPU
    enc_seq_length = input_sequence_length
    dec_seq_length = 1  # a decoder sequence length is always one because it's just the last generated token
    input_ids = torch.ones(batch_size, enc_seq_length, dtype=torch.int64)
    attention_mask = torch.ones(batch_size, enc_seq_length, dtype=torch.int64)

    n_heads = model_config.num_heads
    d_kv = model_config.d_kv

    input_ids_dec = torch.ones(batch_size, dec_seq_length, dtype=torch.int64)
    attention_mask_dec = torch.ones(batch_size, dec_seq_length, dtype=torch.int64)
    enc_out = torch.ones(
        (batch_size, enc_seq_length, model_config.d_model), dtype=torch.float32
    )

    # self_attention_past_key_values = torch.ones(
    #     (model_config.num_decoder_layers, 2, batch_size, n_heads, seq_length_a, d_kv), dtype=torch.float32)
    # cross_attention_past_key_values = torch.ones(
    #     (model_config.num_decoder_layers, 2, batch_size, n_heads, seq_length_b, d_kv), dtype=torch.float32)

    sa = torch.ones(
        (batch_size, n_heads, dec_seq_length, d_kv), dtype=torch.float32
    )  # 1, 8, 1, 64
    ca = torch.ones(
        (batch_size, n_heads, enc_seq_length, d_kv), dtype=torch.float32
    )  # 1, 8, variable, 64
    t5_block = (sa, sa, ca, ca)
    past_key_values = (t5_block,) * model_config.num_decoder_layers

    flat_past_key_values = functools.reduce(operator.iconcat, past_key_values, [])

    decoder_all_inputs = tuple(
        [input_ids_dec, attention_mask_dec, enc_out] + flat_past_key_values
    )

    # for progress bars
    bar = Bar("Exporting to onnx...", max=3)

    import warnings

    # ignores all the warnings during conversion
    warnings.filterwarnings("ignore")

    # Exports to ONNX
    with torch.no_grad():

        decoder_inputs = [
            "input_ids",
            "encoder_attention_mask",
            "encoder_hidden_states",
        ]

        pkv_input_names = ["pkv_{}".format(i) for i in range(len(flat_past_key_values))]

        decoder_input_names = decoder_inputs + pkv_input_names

        decoder_output_names = ["logits", "output_past_key_values"]

        dyn_axis_general = {0: "batch", 1: "sequence"}
        dyn_axis_pkv = {0: "batch", 2: "seq_length"}

        dyn_axis = {
            "input_ids": dyn_axis_general,
            "encoder_attention_mask": dyn_axis_general,
            "encoder_hidden_states": dyn_axis_general,
            "logits": dyn_axis_general,
            "output_past_key_values": dyn_axis_general,
        }

        dyn_pkv = {
            "pkv_{}".format(i): dyn_axis_pkv
            for i in range(len(flat_past_key_values))
        }

        dyn_axis_params = {**dyn_axis, **dyn_pkv}

        # decoder to utilize past key values:
        torch.onnx.export(
            decoder_with_lm_head,
            decoder_all_inputs,
            decoder_path.as_posix(),
            export_params=True,
            do_constant_folding=True,
            opset_version=onnx_opset_version,
            input_names=decoder_input_names,
            output_names=decoder_output_names,
            dynamic_axes=dyn_axis_params,
        )
        bar.next()

        torch.onnx.export(
            simplified_encoder,
            args=(input_ids, attention_mask),
            f=encoder_path.as_posix(),
            export_params=True,
            opset_version=onnx_opset_version,
            do_constant_folding=True,
            input_names=["input_ids", "attention_mask"],
            output_names=["hidden_states"],
            dynamic_axes={
                "input_ids": dyn_axis_general,
                "attention_mask": dyn_axis_general,
                "hidden_states": dyn_axis_general,
            },
        )
        bar.next()
        # initial decoder to produce past key values
        torch.onnx.export(
            decoder_with_lm_head_init,
            (input_ids_dec, attention_mask_dec, enc_out),
            init_decoder_path.as_posix(),
            export_params=True,
            opset_version=onnx_opset_version,
            input_names=[
                "input_ids",
                "encoder_attention_mask",
                "encoder_hidden_states",
            ],
            output_names=["logits", "past_key_values"],
            dynamic_axes={
                # batch_size, seq_length = input_shape
                "input_ids": dyn_axis_general,
                "encoder_attention_mask": dyn_axis_general,
                "encoder_hidden_states": dyn_axis_general,
                "logits": dyn_axis_general,
                "past_key_values": dyn_axis_general,
            },
        )
        bar.next()
        bar.finish()

    return encoder_path, decoder_path, init_decoder_path


def get_model_paths(pretrained_model, model_path, quantized):

    model_path.mkdir(parents=True, exist_ok=True)

    # gets only the filename
    pretrained_model_name = Path(pretrained_model).stem

    if not quantized:
        encoder_path = model_path.joinpath(f"{pretrained_model_name}-encoder.onnx")
        decoder_path = model_path.joinpath(f"{pretrained_model_name}-decoder.onnx")
        init_decoder_path = model_path.joinpath(
            f"{pretrained_model_name}-init-decoder.onnx"
        )
    else:
        encoder_path = model_path.joinpath(
            f"{pretrained_model_name}-encoder-quantized.onnx"
        )
        decoder_path = model_path.joinpath(
            f"{pretrained_model_name}-decoder-quantized.onnx"
        )
        init_decoder_path = model_path.joinpath(
            f"{pretrained_model_name}-init-decoder-quantized.onnx"
        )

    return encoder_path, decoder_path, init_decoder_path


def quantize(models_name_or_path):
    """
    Quantize the weights of the model from float32 to in8 to allow very efficient inference on modern CPU

    Uses unsigned ints for activation values, signed ints for weights, per
    https://onnxruntime.ai/docs/performance/quantization.html#data-type-selection
    it is faster on most CPU architectures
    Args:
        onnx_model_path: Path to location the exported ONNX model is stored
    Returns: The Path generated for the quantized
    """
    from onnxruntime.quantization import quantize_dynamic, QuantType

    bar = Bar("Quantizing...", max=3)

    quant_model_paths = []
    for model in models_name_or_path:
        model_name = model.as_posix()
        output_model_name = f"{model_name[:-5]}-quantized.onnx"
        quantize_dynamic(
            model_input=model_name,
            model_output=output_model_name,
            per_channel=True,
            reduce_range=True, # should be the same as per_channel
            activation_type=QuantType.QUInt8,
            weight_type=QuantType.QInt8,  # per docs, signed is faster on most CPUs
            optimize_model=False,
        )  # op_types_to_quantize=['MatMul', 'Relu', 'Add', 'Mul' ],
        quant_model_paths.append(output_model_name)
        bar.next()

    bar.finish()

    return tuple(quant_model_paths)