text-generation-inference/server/text_generation_server/layers/eetq.py
Daniël de Kok 2dd680b799 Improve the handling of quantized weights (#2250)
* Improve the handling of quantized weights

Handling of quantized weights was split between two mechanisms:

- For quantized checkpoints, we used the new weight loader
  infrastructure.
- For quantization while loading (EETQ, FP8, bitsandbytes) we
  instead relied on conditional in `get_linear`.

Weight loaders support context managers to selectively load
particular layers with different weight loaders, which is useful
for models like Idefics2 AWQ, which uses a quantized text model,
but unquantized vision and connector models. However, the context
manager would be overrided by `get_linear`, which string-checks
`quantizer`. Also, the context manager would not work with
EETQ, FP8, and bitsandbytes.

This change migrates all quantizers to the weight loader infrastructure.
This has several benefits:

- We can use context managers with all quantizers.
- All the implementation details move down to the quantizer layers,
  `get_linear` does not need to know how to handle quantizer linear
  layers.
- All quantizer weights are strongly typed, we don't pass around
  raw tensors.
- We don't have to pass around the `quantizer` string everywhere.

* Exclude non-MLP layers when using FP8 quantization with Llama
2024-09-25 05:27:40 +00:00

44 lines
1.3 KiB
Python

from dataclasses import dataclass
import torch
from EETQ import quant_weights, w8_a16_gemm
from text_generation_server.utils.weights import Weight
@dataclass
class EETQWeight(Weight):
weight: torch.Tensor
def get_linear(self, bias: torch.Tensor):
try:
from text_generation_server.layers.eetq import EETQLinear
return EETQLinear(self.weight, bias)
except ImportError:
raise ImportError(
"Please install EETQ from https://github.com/NetEase-FuXi/EETQ"
)
class EETQLinear(torch.nn.Module):
def __init__(
self,
weight,
bias,
) -> None:
super().__init__()
device = weight.device
if weight.dtype != torch.float16:
weight = weight.to(dtype=torch.float16)
weight = torch.t(weight).contiguous().cpu()
weight, scale = quant_weights(weight, torch.int8, False)
self.weight = weight.cuda(device)
self.scale = scale.cuda(device)
self.bias = bias.cuda(device) if bias is not None else None
def forward(self, input: torch.Tensor) -> torch.Tensor:
output = w8_a16_gemm(input, self.weight, self.scale)
output = output + self.bias if self.bias is not None else output
return output