modity code structure
Former-commit-id: 0682ed357210897e0b67c4a6eb31a94b3eb929f1
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src/llmtuner/tuner/ppo/__init__.py
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src/llmtuner/tuner/ppo/__init__.py
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from llmtuner.tuner.ppo.workflow import run_ppo
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src/llmtuner/tuner/ppo/trainer.py
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src/llmtuner/tuner/ppo/trainer.py
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import os
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import math
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import torch
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from tqdm import tqdm
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from typing import Callable, Dict, List, Optional
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from transformers import Seq2SeqTrainingArguments, TrainerState, TrainerControl
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from transformers.modeling_utils import PreTrainedModel
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from trl import PPOTrainer
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from trl.core import LengthSampler
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from llmtuner.extras.callbacks import LogCallback
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from llmtuner.extras.logging import get_logger
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from llmtuner.extras.misc import AverageMeter, get_logits_processor
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from llmtuner.hparams import FinetuningArguments
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from llmtuner.tuner.core.trainer import PeftTrainer
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from llmtuner.tuner.ppo.utils import cast_layernorm_dtype, replace_model
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logger = get_logger(__name__)
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class PPOPeftTrainer(PPOTrainer, PeftTrainer):
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r"""
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Inherits PPOTrainer.
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"""
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def __init__(
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self,
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training_args: Seq2SeqTrainingArguments,
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finetuning_args: FinetuningArguments,
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callbacks: List[LogCallback],
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**kwargs
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):
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PPOTrainer.__init__(self, **kwargs)
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self.args = training_args
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self.finetuning_args = finetuning_args
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self.log_callback = callbacks[0]
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self.state = TrainerState()
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self.control = TrainerControl()
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self.data_collator = self.accelerator.prepare(kwargs["data_collator"]) # override the data collator of PPOTrainer
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def ppo_train(self, max_target_length: int) -> None:
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r"""
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Implements training loop for the PPO stage, like _inner_training_loop() in Huggingface's Trainer.
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"""
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total_train_batch_size = self.config.batch_size * self.config.gradient_accumulation_steps * self.args.world_size
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len_dataloader = len(self.dataloader)
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num_steps_per_epoch = max(len_dataloader // self.config.gradient_accumulation_steps, 1)
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num_examples = len(self.dataset)
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num_train_epochs = self.args.num_train_epochs
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max_steps = math.ceil(num_train_epochs * num_steps_per_epoch)
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self.state.max_steps = max_steps
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self.state.num_train_epochs = num_train_epochs
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self.state.is_local_process_zero = self.is_local_process_zero()
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self.state.is_world_process_zero = self.is_world_process_zero()
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if self.is_world_process_zero():
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logger.info("***** Running training *****")
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logger.info(f" Num examples = {num_examples}")
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logger.info(f" Num Epochs = {num_train_epochs}")
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logger.info(f" Instantaneous batch size per device = {self.config.batch_size}")
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logger.info(f" Total train batch size (w. parallel, distributed & accumulation) = {total_train_batch_size}")
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logger.info(f" Gradient Accumulation steps = {self.config.gradient_accumulation_steps}")
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logger.info(f" Total optimization steps = {max_steps}")
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logger.info(f" Number of trainable parameters = {sum(p.numel() for p in self.model.parameters() if p.requires_grad)}")
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# Keyword arguments for `model.generate`
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gen_kwargs = {
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"top_k": 0.0,
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"top_p": 1.0,
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"do_sample": True,
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"pad_token_id": self.tokenizer.pad_token_id,
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"eos_token_id": self.tokenizer.eos_token_id,
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"logits_processor": get_logits_processor()
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}
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output_length_sampler = LengthSampler(max_target_length // 2, max_target_length)
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unwrapped_model: PreTrainedModel = self.accelerator.unwrap_model(self.model)
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dataiter = iter(self.dataloader)
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steps_trained = 0
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loss_meter = AverageMeter()
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reward_meter = AverageMeter()
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self.log_callback.on_train_begin(self.args, self.state, self.control)
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for step in tqdm(range(max_steps), disable=not self.is_world_process_zero(), leave=False):
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for _ in range(self.config.gradient_accumulation_steps):
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batch = next(dataiter)
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steps_trained += 1
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unwrapped_model.gradient_checkpointing_disable()
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unwrapped_model.config.use_cache = True
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# Get response from model
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query_tensors: torch.Tensor = batch["input_ids"]
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response_tensors = self.generate(batch, length_sampler=output_length_sampler, return_prompt=False, **gen_kwargs)
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queries: List[torch.Tensor] = []
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responses: List[torch.Tensor] = []
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for i in range(len(query_tensors)):
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query_length = (query_tensors[i] != self.tokenizer.pad_token_id).nonzero()[0]
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response_length = (response_tensors[i] != self.tokenizer.pad_token_id).nonzero()[-1] + 1
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queries.append(query_tensors[i, query_length:]) # remove padding from left
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if response_length < 2: # make response have at least 2 tokens
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responses.append(response_tensors.new_empty(2).fill_(self.tokenizer.eos_token_id))
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else:
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responses.append(response_tensors[i, :response_length]) # remove padding from right
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# Compute rewards
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replace_model(unwrapped_model, target="reward")
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_, _, values = self.model(**self.prepare_model_inputs(queries, responses))
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rewards = [reward for reward in values[:, -1].to(torch.float32)] # use float32 type
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replace_model(unwrapped_model, target="default") # make sure the model is default at the end
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# Run PPO step
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unwrapped_model.gradient_checkpointing_enable()
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unwrapped_model.config.use_cache = False
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stats = self.step(queries, responses, rewards)
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loss_meter.update(stats["ppo/loss/total"], n=len(rewards))
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reward_meter.update(torch.stack(rewards).mean().item(), n=len(rewards))
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if self.control.should_epoch_stop or self.control.should_training_stop:
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break
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if steps_trained == len_dataloader:
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dataiter = iter(self.dataloader)
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steps_trained = 0
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if self.is_world_process_zero() and (step+1) % self.args.logging_steps == 0:
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logs = {
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"loss": round(loss_meter.avg, 4),
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"reward": round(reward_meter.avg, 4),
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"learning_rate": stats["ppo/learning_rate"],
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"epoch": round(step / num_steps_per_epoch, 2)
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}
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print(logs)
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logs["step"] = step
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self.state.log_history.append(logs)
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self.log_callback.on_log(self.args, self.state, self.control)
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loss_meter.reset()
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reward_meter.reset()
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if (step+1) % self.args.save_steps == 0: # save checkpoint
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self.save_model(os.path.join(self.args.output_dir, f"checkpoint-{step+1}"))
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if self.control.should_training_stop:
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break
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@torch.no_grad()
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def generate(
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self,
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inputs: Dict[str, torch.Tensor],
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length_sampler: Optional[Callable] = None,
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return_prompt: Optional[bool] = True,
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**generation_kwargs
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) -> torch.Tensor:
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r"""
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Generates model's responses given queries.
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Subclass and override to inject custom behavior.
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"""
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self.model, layer_norm_params = cast_layernorm_dtype(self.model)
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if length_sampler is not None:
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generation_kwargs["max_new_tokens"] = length_sampler()
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unwrapped_model = self.accelerator.unwrap_model(self.model)
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response = unwrapped_model.generate(**inputs, **generation_kwargs)
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# Temporary hack to ensure the generation config is not initialized for each iteration of the evaluation loop
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# Inspired by: https://github.com/huggingface/transformers/blob/v4.28.1/src/transformers/trainer_seq2seq.py#L273
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if unwrapped_model.pretrained_model.generation_config._from_model_config:
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unwrapped_model.pretrained_model.generation_config._from_model_config = False
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self.model, _ = cast_layernorm_dtype(self.model, layer_norm_params)
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if not return_prompt and not self.is_encoder_decoder:
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return response[:, inputs["input_ids"].size(1):]
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return response
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def save_model(self, output_dir: Optional[str] = None) -> None:
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r"""
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Saves model checkpoint.
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Subclass and override to inject custom behavior.
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"""
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if self.args.should_save:
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self._save(output_dir)
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37
src/llmtuner/tuner/ppo/utils.py
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src/llmtuner/tuner/ppo/utils.py
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import torch
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from typing import Dict, List, Literal, Optional, Tuple
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from trl import AutoModelForCausalLMWithValueHead
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from llmtuner.extras.constants import LAYERNORM_NAMES
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def replace_model(model: AutoModelForCausalLMWithValueHead, target: Literal["default", "reward"]) -> None:
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if target == "reward": # save default head temporarily
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valuehead_state_dict = model.v_head.state_dict()
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setattr(model, "default_head_weight", valuehead_state_dict["summary.weight"])
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setattr(model, "default_head_bias", valuehead_state_dict["summary.bias"])
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model.pretrained_model.set_adapter(target) # set the LoRA adapter to be active
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model.v_head.load_state_dict({
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"summary.weight": getattr(model, "{}_head_weight".format(target)),
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"summary.bias": getattr(model, "{}_head_bias".format(target))
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})
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def cast_layernorm_dtype(
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model: AutoModelForCausalLMWithValueHead,
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layer_norm_names: List[str] = LAYERNORM_NAMES,
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layer_norm_params: Optional[Dict[str, torch.Tensor]] = None
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) -> Tuple[AutoModelForCausalLMWithValueHead, Dict[str, torch.Tensor]]:
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layer_norm_state_dict = {}
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for name, param in model.named_parameters():
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if param.ndim == 1 and any(layer_norm_name in name for layer_norm_name in layer_norm_names):
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if layer_norm_params is not None:
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param.data = layer_norm_params[name] # restore float32 weights
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else:
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layer_norm_state_dict[name] = param.data.detach().clone() # store float32 weights for stability
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param.data = param.data.to(torch.float16)
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return model, layer_norm_state_dict
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src/llmtuner/tuner/ppo/workflow.py
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src/llmtuner/tuner/ppo/workflow.py
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# Inspired by:
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# https://github.com/lvwerra/trl/blob/main/examples/sentiment/scripts/gpt-neox-20b_peft/gpt-neo-20b_sentiment_peft.py
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import math
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from trl import PPOConfig
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from torch.optim import AdamW
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from transformers import DataCollatorForSeq2Seq, Seq2SeqTrainingArguments
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from transformers.optimization import get_scheduler
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from llmtuner.dsets import get_dataset, preprocess_dataset
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from llmtuner.extras.callbacks import LogCallback
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from llmtuner.extras.ploting import plot_loss
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from llmtuner.hparams import ModelArguments, DataArguments, FinetuningArguments
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from llmtuner.tuner.core import load_model_and_tokenizer
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from llmtuner.tuner.ppo.trainer import PPOPeftTrainer
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def run_ppo(
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model_args: ModelArguments,
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data_args: DataArguments,
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training_args: Seq2SeqTrainingArguments,
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finetuning_args: FinetuningArguments
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):
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dataset = get_dataset(model_args, data_args)
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model, tokenizer = load_model_and_tokenizer(model_args, finetuning_args, training_args.do_train, stage="ppo")
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dataset = preprocess_dataset(dataset, tokenizer, data_args, training_args, stage="ppo")
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data_collator = DataCollatorForSeq2Seq(tokenizer=tokenizer, label_pad_token_id=tokenizer.pad_token_id)
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ppo_config = PPOConfig(
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model_name=model_args.model_name_or_path,
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learning_rate=training_args.learning_rate,
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mini_batch_size=training_args.per_device_train_batch_size,
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batch_size=training_args.per_device_train_batch_size,
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gradient_accumulation_steps=training_args.gradient_accumulation_steps,
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ppo_epochs=1,
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max_grad_norm=training_args.max_grad_norm
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)
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optimizer = AdamW(filter(lambda p: p.requires_grad, model.parameters()), lr=ppo_config.learning_rate)
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total_train_batch_size = \
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training_args.per_device_train_batch_size * training_args.gradient_accumulation_steps * training_args.world_size
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lr_scheduler = get_scheduler(
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training_args.lr_scheduler_type,
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optimizer=optimizer,
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num_warmup_steps=training_args.warmup_steps,
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num_training_steps=(training_args.num_train_epochs * math.ceil(len(dataset) / total_train_batch_size))
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)
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# Initialize our Trainer
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ppo_trainer = PPOPeftTrainer(
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training_args=training_args,
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finetuning_args=finetuning_args,
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callbacks=[LogCallback()],
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config=ppo_config,
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model=model,
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ref_model=None,
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tokenizer=tokenizer,
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dataset=dataset,
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data_collator=data_collator,
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optimizer=optimizer,
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lr_scheduler=lr_scheduler
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)
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ppo_trainer.ppo_train(max_target_length=data_args.max_target_length)
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ppo_trainer.save_model()
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ppo_trainer.save_state() # must be after save_model
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if ppo_trainer.is_world_process_zero() and model_args.plot_loss:
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plot_loss(training_args.output_dir, keys=["loss", "reward"])
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