llama-stack/llama_toolchain/inference/quantization/loader.py
2024-07-23 08:32:33 -07:00

105 lines
3.7 KiB
Python

# Copyright (c) Meta Platforms, Inc. and affiliates.
# All rights reserved.
#
# This source code is licensed under the terms described in the LICENSE file in
# the root directory of this source tree.
# Copyright (c) Meta Platforms, Inc. and affiliates.
# This software may be used and distributed in accordance with the terms of the Llama 3 Community License Agreement.
import os
from typing import Optional
import torch
from fairscale.nn.model_parallel.mappings import reduce_from_model_parallel_region
from llama_models.llama3_1.api.model import Transformer, TransformerBlock
from llama_toolchain.inference.api.config import (
CheckpointQuantizationFormat,
InlineImplConfig,
)
from llama_toolchain.inference.api.datatypes import QuantizationType
from termcolor import cprint
from torch import Tensor
def is_fbgemm_available() -> bool:
try:
import fbgemm_gpu.experimental.gen_ai # noqa: F401
return True
except ImportError:
return False
def swiglu_wrapper(
self,
x: Tensor,
):
from .fp8_impls import ffn_swiglu
out = ffn_swiglu(x, self.w1.weight, self.w3.weight, self.w2.weight)
return reduce_from_model_parallel_region(out)
def convert_to_quantized_model(
model: Transformer,
config: InlineImplConfig,
fp8_activation_scale_ub: Optional[float] = 1200.0,
) -> Transformer:
if config.quantization.type == QuantizationType.bf16.value:
return model
elif config.quantization.type != QuantizationType.fp8.value:
raise ValueError("Only FP8 quantization is supported")
from .fp8_impls import Fp8ScaledWeights, load_fp8, quantize_fp8
checkpoint = config.checkpoint_config.checkpoint
# Move weights to GPU with quantization
if checkpoint.quantization_format == CheckpointQuantizationFormat.fp8_mixed.value:
cprint("Loading fp8 scales...", "yellow")
fp8_scales_path = os.path.join(
checkpoint.checkpoint_dir, f"fp8_scales_{get_model_parallel_rank()}.pt"
)
assert os.path.isfile(
fp8_scales_path
), f"fp8_scales_path not found for rank {get_model_parallel_rank()}"
fp8_scales = torch.load(fp8_scales_path, weights_only=True)
for block in model.layers:
if isinstance(block, TransformerBlock):
if block.layer_id == 0 or block.layer_id == (model.n_layers - 1):
continue
block.feed_forward.forward = swiglu_wrapper.__get__(block.feed_forward)
for key in ("w1", "w3", "w2"):
param = getattr(block.feed_forward, key)
param.weight = load_fp8(
param.weight,
fp8_scales[
f"{block.layer_id}_feed_forward.{key}_{get_model_parallel_rank()}"
],
fp8_activation_scale_ub,
)
else:
cprint("Quantizing fp8 weights from bf16...", "yellow")
for block in model.layers:
if isinstance(block, TransformerBlock):
if block.layer_id == 0 or block.layer_id == (model.n_layers - 1):
continue
block.feed_forward.forward = swiglu_wrapper.__get__(block.feed_forward)
for key in ("w1", "w3", "w2"):
param = getattr(block.feed_forward, key)
param.weight = quantize_fp8(
param.weight,
fp8_activation_scale_ub,
output_device=torch.device("cuda"),
)
for _, parameter in model.named_parameters():
if not isinstance(parameter, Fp8ScaledWeights):
parameter.data = parameter.to(device="cuda")
return model