support autoTP with weight only quantization in DS inference path

[ftian1]

This PR is used to make weight only quantization work with autoTP.

The sample code is like below:

    model = AutoModelForCausalLM.from_pretrained(model_id, torch_dtype=torch.float16).to(device)

    ds_model = deepspeed.init_inference(model,
                                        mp_size=world_size,
                                        dtype=torch.float16,
                                        replace_with_kernel_inject=False) 

    model = ds_model.module
    from deepspeed.inference.quantization.quantization import _init_group_wise_weight_quantization
    ds_config = {
        "weight_quantization": {
            "post_init_quant": {
                '*': {
                    'num_bits': 4,
                    'group_size': 32,
                    'group_dim': 1,
                    'symmetric': False
                },
            }
        }
    }
    model = _init_group_wise_weight_quantization(model, ds_config)

by this way, user can enable WOQ on multiple cards.

[delock]

@ftian1 if accelerator other than CUDA want to support AutoTP WOQ, which set of OpBuilder/kernels needs to be implemented? Can you provide a link to kernel usage in the code?

[ftian1]

@ftian1 if accelerator other than CUDA want to support AutoTP WOQ, which set of OpBuilder/kernels needs to be implemented? Can you provide a link to kernel usage in the code?

Here is the link https://github.com/microsoft/DeepSpeed/blob/master/deepspeed/inference/quantization/utils.py#L115-L124, in which it dispatch to deepspeed.ops.op_builder.QuantizerBuilder() if device is cuda and group_size is able to be divided by 8. such implementation could be enhanced to support different h/w's opbuilder

[delock]

It should be better to detect custom kernel existance by check attribute of the loaded ops, and call custom kernel accordingly, so any accelerator implement these kernels would be plugged.

@ftian1 if accelerator other than CUDA want to support AutoTP WOQ, which set of OpBuilder/kernels needs to be implemented? Can you provide a link to kernel usage in the code?

Here is the link https://github.com/microsoft/DeepSpeed/blob/master/deepspeed/inference/quantization/utils.py#L115-L124, in which it dispatch to deepspeed.ops.op_builder.QuantizerBuilder() if device is cuda and group_size is able to be divided by 8. such implementation could be enhanced to support different h/w's opbuilder

[delock]

@ftian1 Is usage of WoQ with AutoTP similiar to with kernel injection? Can you post a sample code show WoQ in DeepSpeed looks like withy kernel injection?