llama: avoid copying logits during prompt decode in MTP#23198
Merged
Conversation
ggerganov
reviewed
May 17, 2026
ggerganov
reviewed
May 17, 2026
CISC
approved these changes
May 17, 2026
ggerganov
approved these changes
May 17, 2026
Member
ggerganov
left a comment
ggerganov
left a comment
There was a problem hiding this comment.
A quick bench on RTX 5090 with Qwen3.6 27B Q4_K
Are the legend colors swapped? |
Member
|
@d-r-e no, MTP does negatively impact prompt processing, but under this PR the negative impact is halved. |
|
2xMI50 qwen 27b Q4_1 does see some improvement with this PR |
Contributor
Why does it affect prompt processing? |
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
7 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Overview
Avoid copying the logits for every token in the batch when doing prompt processing for MTP since it only requires the pre-norm. This reduces memory traffic quite a bit and in turn increases PP speed with MTP.
Additional information
Requirements