78 lines
2.4 KiB
Python
78 lines
2.4 KiB
Python
# Copyright (c) Facebook, Inc. and its affiliates.
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#
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# This source code is licensed under the MIT license found in the
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# LICENSE file in the root directory of this source tree.
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import logging
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from operator import attrgetter
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import torch.distributed as dist
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import torch.nn as nn
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from ..pq.utils import attrsetter, get_layers
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from .modules import ActivationQuantizer, IntConv2d, IntEmbedding, IntLinear
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MAPPING = {nn.Linear: IntLinear, nn.Embedding: IntEmbedding, nn.Conv2d: IntConv2d}
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def quantize_model_(model, p=0.2, bits=8, update_step=3000):
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"""
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Replaces all modules with their scalar quantized counterpart and
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registers hooks to quantize the post-ativations of those modules.
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Args:
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- model: a nn.Module
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- p: amount of noise (0 for no noise, 1 to quantize all the weights/activations)
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- bits: number of bits
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- update_step: update quantization parameters every update_step steps
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"""
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# quantize all layers
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quantized_layers = get_layers(model, "(.*?)")
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for layer in quantized_layers:
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# book-keeping
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is_master_process = (not dist.is_initialized()) or (
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dist.is_initialized() and dist.get_rank() == 0
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)
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# recover module
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module = attrgetter(layer)(model)
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if is_master_process:
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logging.info(
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f"Quantizing layer {layer} with bits={bits} and QuantNoise={p}"
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)
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# quantization params
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q_params = {
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"p": p,
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"update_step": update_step,
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"bits": bits,
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"method": "histogram",
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"counter": 0,
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}
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# instantiate the quantized counterpart
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if isinstance(module, tuple(MAPPING.keys())):
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QuantizedModule = MAPPING[module.__class__]
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quantized_module = QuantizedModule.__new__(QuantizedModule)
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params = module.__dict__
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params.update(q_params)
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quantized_module.__dict__.update(params)
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else:
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if is_master_process:
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logging.info(f"Module {module} not yet supported for quantization")
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continue
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# activation quantization
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a_q = ActivationQuantizer(quantized_module, p=0, bits=bits, method="histogram")
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# replace layer by its quantized counterpart
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attrsetter(layer)(model, quantized_module)
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# return name of quantized layers
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return quantized_layers
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