Skip to content

[Bugfix] Fix DeepseekV32 AssertionError: num_kv_heads == 1 #33086

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Closed
chaunceyjiang wants to merge 2 commits into from
Closed

[Bugfix] Fix DeepseekV32 AssertionError: num_kv_heads == 1 #33086

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
a11ec24
[Bugfix] Fix DeepseekV32 AssertionError: num_kv_heads == 1
chaunceyjiang Jan 26, 2026
47c9462
Merge branch 'main' into pd_dsv32_2
chaunceyjiang Jan 26, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
1 change: 0 additions & 1 deletion vllm/v1/attention/backends/mla/indexer.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -49,7 +49,6 @@ def get_kv_cache_shape(
head_size: int,
cache_dtype_str: str = "auto",
) -> tuple[int, ...]:
assert num_kv_heads == 1
Copy link
Copy Markdown
Collaborator Author

@chaunceyjiang chaunceyjiang Jan 26, 2026 •
edited
Loading

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

vllm/vllm/distributed/kv_transfer/kv_connector/utils.py

Lines 322 to 326 in 64e3d67

# Figure out whether the first dimension of the cache is K/V
# or num_blocks. This is used to register the memory regions correctly.
kv_cache_shape = self.attn_backend.get_kv_cache_shape(
num_blocks=1, block_size=16, num_kv_heads=4, head_size=1
)

/cc @NickLucche

I’m not sure whether this fix is correct. PTAL.

Copy link
Copy Markdown
Collaborator

@NickLucche NickLucche Jan 26, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

@chaunceyjiang I think the issue is in how we're using the function, let me look into it

Copy link
Copy Markdown
Collaborator

@NickLucche NickLucche Jan 26, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

#33090

Copy link
Copy Markdown
Collaborator Author

@chaunceyjiang chaunceyjiang Jan 26, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Hi @NickLucche, for a change like #33090, I’m inclined to remove this assert. This would make the use of get_kv_cache_shape more flexible.

Copy link
Copy Markdown
Collaborator Author

@chaunceyjiang chaunceyjiang Jan 26, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

same as: FlashMLASparseBackend

Copy link
Copy Markdown
Collaborator Author

@chaunceyjiang chaunceyjiang Jan 27, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

@NickLucche WDYT?

return (num_blocks, block_size, head_size)

@staticmethod
Expand Down