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Author SHA1 Message Date
AmirX0 8acbed85ff
Merge 5b26153b75 into 7a9137d2e9 2026-09-15 19:34:49 +08:00
jingyaogong 7a9137d2e9 [update] trim verbose ddp comments 2026-09-15 14:53:11 +08:00
jingyaogong 7988bc81a3
Merge pull request #855 from basil-k-aji-dev/perf/ddp-followups
[perf] skip the per-forward RoPE buffer broadcast in the RL trainers
2026-09-15 14:51:37 +08:00
basil-k-aji-dev 37ac206e9a [perf] skip the per-forward RoPE buffer broadcast in the RL trainers
Follow-up to the review on #854.

DDP re-broadcasts every registered buffer from rank 0 on each forward. The only
buffers here are freqs_cos / freqs_sin, which each rank computes deterministically
from config and never mutates from data, so the broadcast moves identical bytes
every step for nothing.

Verified with a two-rank CPU/Gloo run: with broadcast_buffers=False the
gradients stay identical across ranks and so do the buffers.

Also document the critic's tied-embedding assumption. CriticModel.forward never
calls lm_head, which is only safe under DDP because tie_word_embeddings (default
True) makes lm_head.weight the same Parameter as embed_tokens.weight. Untied, it
becomes a genuinely unused parameter and DDP raises.
2026-09-14 22:22:00 +05:30
AmirX0 5b26153b75 fix: make repetition penalty multilingual 2026-09-01 07:03:34 +03:30
5 changed files with 79 additions and 28 deletions

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@ -0,0 +1,43 @@
import unittest
from trainer.reward_utils import rep_penalty
class StubTokenizer:
def __init__(self, token_ids):
self.token_ids = token_ids
self.calls = []
def encode(self, text, add_special_tokens=True):
self.calls.append((text, add_special_tokens))
return self.token_ids
class RepetitionPenaltyTests(unittest.TestCase):
def test_repeated_chinese_tokens_receive_penalty(self):
tokenizer = StubTokenizer([1, 2, 1, 2, 1, 2, 1, 2, 1, 2])
self.assertEqual(rep_penalty("你好你好你好你好你好", tokenizer), 0.5)
self.assertEqual(tokenizer.calls, [("你好你好你好你好你好", False)])
def test_repeated_english_tokens_receive_penalty_case_insensitively(self):
tokenizer = StubTokenizer([3, 3, 3, 3])
self.assertEqual(rep_penalty("Hello HELLO hello hello", tokenizer), 0.5)
self.assertEqual(tokenizer.calls, [("hello hello hello hello", False)])
def test_unique_and_short_sequences_have_no_penalty(self):
self.assertEqual(rep_penalty("unique", StubTokenizer([1, 2, 3, 4, 5])), 0.0)
self.assertEqual(rep_penalty("short", StubTokenizer([1, 2])), 0.0)
def test_invalid_configuration_is_rejected(self):
tokenizer = StubTokenizer([])
with self.assertRaisesRegex(ValueError, "n must be greater than zero"):
rep_penalty("text", tokenizer, n=0)
with self.assertRaisesRegex(ValueError, "cap must be non-negative"):
rep_penalty("text", tokenizer, cap=-0.1)
if __name__ == "__main__":
unittest.main()

19
trainer/reward_utils.py Normal file
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@ -0,0 +1,19 @@
def rep_penalty(text, tokenizer, n=3, cap=0.5):
r"""Return a capped repetition penalty over model-token n-grams.
Token IDs keep the calculation consistent across languages. In particular,
contiguous CJK text must not be treated as one word, which is what happens
with a ``\w+``-based regular expression.
"""
if n <= 0:
raise ValueError("n must be greater than zero")
if cap < 0:
raise ValueError("cap must be non-negative")
token_ids = tokenizer.encode(text.lower(), add_special_tokens=False)
grams = [tuple(token_ids[i:i + n]) for i in range(len(token_ids) - n + 1)]
if not grams:
return 0.0
repeated = len(grams) - len(set(grams))
return min(cap, repeated * cap * 2 / len(grams))

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@ -25,16 +25,12 @@ from model.model_minimind import MiniMindConfig, MiniMindForCausalLM
from dataset.lm_dataset import AgentRLDataset
from trainer.trainer_utils import Logger, is_main_process, lm_checkpoint, init_distributed_mode, setup_seed, SkipBatchSampler, init_model, LMForRewardModel, safe_math_eval
from trainer.rollout_engine import create_rollout_engine, compute_per_token_logps
from trainer.reward_utils import rep_penalty
warnings.filterwarnings('ignore')
# ================================ 工具与 Reward = Start ================================
def rep_penalty(text, n=3, cap=0.5):
toks = re.findall(r"\w+|[^\w\s]", text.lower())
grams = [tuple(toks[i:i + n]) for i in range(len(toks) - n + 1)]
return min(cap, (len(grams) - len(set(grams))) * cap * 2 / len(grams)) if grams else 0.0
# ======== 工具定义 ========
TOOLS = [
{"type": "function", "function": {"name": "calculate_math", "description": "计算数学表达式", "parameters": {"type": "object", "properties": {"expression": {"type": "string"}}, "required": ["expression"]}}},
@ -214,7 +210,7 @@ def calculate_rewards(prompts, completions, gt_batch, tools_batch, num_gen, rewa
messages = [{"role": role, "content": content.strip()} for role, content in matches]
score = reward_model.get_score(messages, answer)
reward += score # RM分
reward -= rep_penalty(answer)
reward -= rep_penalty(answer, tokenizer)
rewards[idx] = max(min(reward, 3.0), -3.0) # 总分Clip
# -------- 有工具调用:执行结果奖励 --------
else:
@ -234,7 +230,7 @@ def calculate_rewards(prompts, completions, gt_batch, tools_batch, num_gen, rewa
verified = validate_gt_in_text(final_text, gt) if gt else set()
if gt: reward += 2.5 * len(verified) / len(gt) # GT分
if unfinished: reward -= 0.5 # 未完成扣分
reward -= rep_penalty(final_text if final_text else answer)
reward -= rep_penalty(final_text if final_text else answer, tokenizer)
rewards[idx] = max(min(reward, 3.0), -3.0) # 总分Clip
return rewards
@ -473,7 +469,8 @@ if __name__ == "__main__":
Logger('torch.compile enabled')
rollout_engine.update_policy(model)
if dist.is_initialized():
model = DistributedDataParallel(model, device_ids=[local_rank])
# 同 train_ppo:RoPE buffer 各 rank 一致,每步广播纯属浪费
model = DistributedDataParallel(model, device_ids=[local_rank], broadcast_buffers=False)
rollout_engine.update_policy(model)
for epoch in range(start_epoch, args.epochs):

View File

@ -24,16 +24,11 @@ from model.model_minimind import MiniMindConfig, MiniMindForCausalLM
from dataset.lm_dataset import RLAIFDataset
from trainer.trainer_utils import Logger, is_main_process, lm_checkpoint, init_distributed_mode, setup_seed, SkipBatchSampler, init_model, LMForRewardModel
from trainer.rollout_engine import create_rollout_engine
from trainer.reward_utils import rep_penalty
warnings.filterwarnings('ignore')
def rep_penalty(text, n=3, cap=0.5):
toks = re.findall(r"\w+|[^\w\s]", text.lower())
grams = [tuple(toks[i:i + n]) for i in range(len(toks) - n + 1)]
return min(cap, (len(grams) - len(set(grams))) * cap * 2 / len(grams)) if grams else 0.0
def calculate_rewards(prompts, responses, reward_model):
rewards = torch.zeros(len(responses), device=args.device)
@ -57,7 +52,7 @@ def calculate_rewards(prompts, responses, reward_model):
rewards[response_idx] += 1.0 if 20 <= len(thinking_content.strip()) <= 300 else -0.5
rewards[response_idx] += 0.25 if response.count('</think>') == 1 else -0.25
answer = answer_content.strip()
rewards[response_idx] -= rep_penalty(answer)
rewards[response_idx] -= rep_penalty(answer, tokenizer)
score = reward_model.get_score(messages, answer)
reward_model_scores.append(score)
@ -314,7 +309,8 @@ if __name__ == "__main__":
Logger('torch.compile enabled')
rollout_engine.update_policy(model)
if dist.is_initialized():
model = DistributedDataParallel(model, device_ids=[local_rank])
# 同 train_ppo:RoPE buffer 各 rank 一致,每步广播纯属浪费
model = DistributedDataParallel(model, device_ids=[local_rank], broadcast_buffers=False)
rollout_engine.update_policy(model)
# ========== 8. 开始训练 ==========

View File

@ -22,21 +22,16 @@ from model.model_minimind import MiniMindConfig, MiniMindForCausalLM
from dataset.lm_dataset import RLAIFDataset
from trainer.trainer_utils import Logger, is_main_process, lm_checkpoint, init_distributed_mode, setup_seed, SkipBatchSampler, init_model, LMForRewardModel
from trainer.rollout_engine import create_rollout_engine
from trainer.reward_utils import rep_penalty
warnings.filterwarnings('ignore')
def rep_penalty(text, n=3, cap=0.5):
toks = re.findall(r"\w+|[^\w\s]", text.lower())
grams = [tuple(toks[i:i + n]) for i in range(len(toks) - n + 1)]
return min(cap, (len(grams) - len(set(grams))) * cap * 2 / len(grams)) if grams else 0.0
# 自定义的Critic模型,继承自MiniMindLM
class CriticModel(MiniMindForCausalLM):
def __init__(self, params):
super().__init__(params)
# 替换lm_head为输出单一价值的线性层
# lm_head 不参与 forward,仅靠 tie_word_embeddings 与 embed_tokens 共享权重,解绑后 DDP 会报未使用参数
self.value_head = nn.Linear(params.hidden_size, 1)
def forward(self, input_ids=None, attention_mask=None, **kwargs):
@ -64,7 +59,7 @@ def calculate_rewards(prompts, responses, reward_model):
rewards[i] += 1.0 if 20 <= len(thinking_content.strip()) <= 300 else -0.5
rewards[i] += 0.25 if response.count('</think>') == 1 else -0.25
answer = answer_content.strip()
rewards[i] -= rep_penalty(answer)
rewards[i] -= rep_penalty(answer, tokenizer)
score = reward_model.get_score(messages, answer)
reward_model_scores.append(score)
@ -429,8 +424,9 @@ if __name__ == "__main__":
Logger('torch.compile enabled')
rollout_engine.update_policy(actor_model)
if dist.is_initialized():
actor_model = DistributedDataParallel(actor_model, device_ids=[local_rank])
critic_model = DistributedDataParallel(critic_model, device_ids=[local_rank])
# freqs_cos/freqs_sin 各 rank 由 config 确定性算出,默认每步广播一次纯属浪费
actor_model = DistributedDataParallel(actor_model, device_ids=[local_rank], broadcast_buffers=False)
critic_model = DistributedDataParallel(critic_model, device_ids=[local_rank], broadcast_buffers=False)
rollout_engine.update_policy(actor_model)
# ========== 8. 开始训练 ==========