microsoft / microsoft/MInference

[Bug]: Unable to run streamingLLM properly on minference with the qwen3-0.6B model.

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bug
Dominant language
Python
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Description

Describe the bug

When I tried to run streamingLLM on minference with the qwen3-0.6B model, I found that the computed token loss was very abnormal compared to other models, such as the qwen2.5 series. The results and the example code are shown below. Even with dense mode, the output is still abnormal.

Image

Code

from transformers import AutoModelForCausalLM, AutoTokenizer
from minference import MInference
import os, torch
import torch.nn.functional as F

os.environ["CUDA_VISIBLE_DEVICES"] = "0"

prompt =
"""
"""

model_name = "/media/public/models/huggingface/Qwen/Qwen3-0.6B"

tokenizer = AutoTokenizer.from_pretrained(model_name)
model = AutoModelForCausalLM.from_pretrained(
model_name,
torch_dtype=torch.bfloat16,
device_map="auto",
trust_remote_code=True,
)

minference_patch = MInference("a_shape", model_name, attn_kwargs={"n_local": 255, "n_init": 1})
model = minference_patch(model)

inputs = tokenizer(prompt, return_tensors="pt").to("cuda")
input_ids = inputs["input_ids"]

with torch.no_grad():
outputs = model(**inputs)
logits = outputs.logits # [1, seq_len, vocab_size]

shifted_logits = logits[:, :-1, :] # [1, seq_len-1, vocab]
shifted_labels = input_ids[:, 1:] # [1, seq_len-1]

log_probs = F.log_softmax(shifted_logits, dim=-1) # log-probs over vocab

token_logprobs = log_probs.gather(2, shifted_labels.unsqueeze(-1)).squeeze(-1) # [1, seq_len-1]

input_tokens = tokenizer.convert_ids_to_tokens(input_ids[0])
print(f"Prompt: {prompt!r}\n")

cnt = 0.0
for i in range(len(token_logprobs[0])):
prev_token = input_tokens[i]
current_token = input_tokens[i + 1]
logprob = token_logprobs[0, i].item()
sum += logprob
print(f"Token {i + 1}: {current_token!r} | log P({current_token} | ... {prev_token}) = {logprob:.4f}")

print(sum)

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First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start with the supplied Python reproduction using MInference in a_shape mode on Qwen3-0.6B, then compare its token log probabilities with dense mode and the reported Qwen2.5 behavior. Done means identifying and correcting the cause of the abnormal computed token loss, with the reproduction producing consistent results across those comparisons.

Written by the indexing model from the issue text.

Assessment

Tech stack
python, pytorch
Domain
machine-learning, performance
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
30/100

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