Add support for prefix caching to the v3 router #2392
Merged
Conversation
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
This change adds support for prefix caching to the v3 router. This is broken up from the backend support to ease reviewing. For now prefix caching is only enabled with `USE_PREFIX_CACHING=1` in this case, the router will switch to `RadixAllocator`. This allocator uses a radix trie to keep track of prefills that were seen prior. If a new prefill is a prefix of a previously-seen prefil, the router will send a request with `prefix_len>0`, which can be used by the backend to decide to reuse KV blocks from the cache, rather than recomputing them. Even though backend support is not added in this PR, the backend will still work with prefix caching enabled. The prefix lengths are just ignored and not used.
Narsil
approved these changes
Aug 12, 2024
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
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Outdated suggestions cannot be applied.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.
What does this PR do?
This change adds support for prefix caching to the v3 router. This is broken up from the backend support to ease reviewing.
For now prefix caching is only enabled with
USE_PREFIX_CACHING=1in this case, the router will switch toRadixAllocator. This allocator uses a radix trie to keep track of prefills that were seen prior. If a new prefill is a prefix of a previously-seen prefil, the router will send a request withprefix_len>0, which can be used by the backend to decide to reuse KV blocks from the cache, rather than recomputing them.Even though backend support is not added in this PR, the backend will still work with prefix caching enabled. The prefix lengths are just ignored and not used.
Before submitting
Pull Request section?
to it if that's the case.
documentation guidelines, and
here are tips on formatting docstrings.
Who can review?
Anyone in the community is free to review the PR once the tests have passed. Feel free to tag
members/contributors who may be interested in your PR.