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""" |
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Usage: |
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python3 -m fastchat.serve.cli --model ~/model_weights/llama-7b |
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""" |
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import argparse |
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import time |
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import torch |
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from transformers import AutoTokenizer, AutoModelForCausalLM |
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from llava.conversation import conv_templates, SeparatorStyle |
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@torch.inference_mode() |
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def generate_stream(tokenizer, model, params, device, |
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context_len=2048, stream_interval=2): |
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"""Adapted from fastchat/serve/model_worker.py::generate_stream""" |
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prompt = params["prompt"] |
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l_prompt = len(prompt) |
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temperature = float(params.get("temperature", 1.0)) |
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max_new_tokens = int(params.get("max_new_tokens", 256)) |
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stop_str = params.get("stop", None) |
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input_ids = tokenizer(prompt).input_ids |
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output_ids = list(input_ids) |
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max_src_len = context_len - max_new_tokens - 8 |
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input_ids = input_ids[-max_src_len:] |
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for i in range(max_new_tokens): |
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if i == 0: |
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out = model( |
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torch.as_tensor([input_ids], device=device), use_cache=True) |
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logits = out.logits |
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past_key_values = out.past_key_values |
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else: |
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attention_mask = torch.ones( |
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1, past_key_values[0][0].shape[-2] + 1, device=device) |
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out = model(input_ids=torch.as_tensor([[token]], device=device), |
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use_cache=True, |
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attention_mask=attention_mask, |
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past_key_values=past_key_values) |
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logits = out.logits |
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past_key_values = out.past_key_values |
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last_token_logits = logits[0][-1] |
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if temperature < 1e-4: |
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token = int(torch.argmax(last_token_logits)) |
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else: |
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probs = torch.softmax(last_token_logits / temperature, dim=-1) |
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token = int(torch.multinomial(probs, num_samples=1)) |
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output_ids.append(token) |
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if token == tokenizer.eos_token_id: |
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stopped = True |
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else: |
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stopped = False |
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if i % stream_interval == 0 or i == max_new_tokens - 1 or stopped: |
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output = tokenizer.decode(output_ids, skip_special_tokens=True) |
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pos = output.rfind(stop_str, l_prompt) |
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if pos != -1: |
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output = output[:pos] |
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stopped = True |
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yield output |
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if stopped: |
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break |
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del past_key_values |
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def main(args): |
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model_name = args.model_name |
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num_gpus = args.num_gpus |
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if args.device == "cuda": |
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kwargs = {"torch_dtype": torch.float16} |
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if num_gpus == "auto": |
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kwargs["device_map"] = "auto" |
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else: |
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num_gpus = int(num_gpus) |
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if num_gpus != 1: |
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kwargs.update({ |
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"device_map": "auto", |
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"max_memory": {i: "13GiB" for i in range(num_gpus)}, |
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}) |
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elif args.device == "cpu": |
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kwargs = {} |
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else: |
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raise ValueError(f"Invalid device: {args.device}") |
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tokenizer = AutoTokenizer.from_pretrained(model_name) |
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model = AutoModelForCausalLM.from_pretrained(model_name, |
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low_cpu_mem_usage=True, **kwargs) |
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if args.device == "cuda" and num_gpus == 1: |
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model.cuda() |
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conv = conv_templates[args.conv_template].copy() |
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while True: |
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try: |
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inp = input(f"{conv.roles[0]}: ") |
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except EOFError: |
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inp = "" |
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if not inp: |
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print("exit...") |
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break |
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conv.append_message(conv.roles[0], inp) |
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conv.append_message(conv.roles[1], None) |
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prompt = conv.get_prompt() |
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params = { |
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"model": model_name, |
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"prompt": prompt, |
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"temperature": args.temperature, |
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"max_new_tokens": args.max_new_tokens, |
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"stop": conv.sep if conv.sep_style == SeparatorStyle.SINGLE else conv.sep2, |
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} |
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print(f"{conv.roles[1]}: ", end="", flush=True) |
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pre = 0 |
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for outputs in generate_stream(tokenizer, model, params, args.device): |
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outputs = outputs[len(prompt) + 1:].strip() |
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outputs = outputs.split(" ") |
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now = len(outputs) |
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if now - 1 > pre: |
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print(" ".join(outputs[pre:now-1]), end=" ", flush=True) |
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pre = now - 1 |
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print(" ".join(outputs[pre:]), flush=True) |
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conv.messages[-1][-1] = " ".join(outputs) |
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if args.debug: |
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print("\n", {"prompt": prompt, "outputs": outputs}, "\n") |
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if __name__ == "__main__": |
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parser = argparse.ArgumentParser() |
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parser.add_argument("--model-name", type=str, default="facebook/opt-350m") |
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parser.add_argument("--num-gpus", type=str, default="1") |
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parser.add_argument("--device", type=str, choices=["cuda", "cpu"], default="cuda") |
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parser.add_argument("--conv-template", type=str, default="v1") |
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parser.add_argument("--temperature", type=float, default=0.7) |
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parser.add_argument("--max-new-tokens", type=int, default=512) |
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parser.add_argument("--debug", action="store_true") |
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args = parser.parse_args() |
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main(args) |
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