Changed scheduler to use deques instead of lists#2290
Changed scheduler to use deques instead of lists#2290WoosukKwon merged 4 commits intovllm-project:mainfrom
Conversation
WoosukKwon
left a comment
WoosukKwon
left a comment
There was a problem hiding this comment.
Hi @NadavShmayo, thanks for submitting the PR! Yes, it seems we should use deque instead of list for the queues in our scheduler. I left some minor comments on the PR. Please take a look at them!
WoosukKwon
left a comment
WoosukKwon
left a comment
There was a problem hiding this comment.
LGTM. I've made some minor changes to accelerate the merge. Thanks again for the PR!
Hey, sorry for the delayed response. Regarding the changes in the Thanks for the review! 😄 |
Co-authored-by: Woosuk Kwon <woosuk.kwon@berkeley.edu>
vllm-project#2290 changed the scheduler seq group lists to be deques for more efficient updates, but missed one place where the `running` deque gets converted back to a list.
Co-authored-by: Woosuk Kwon <woosuk.kwon@berkeley.edu>
2 participants
Currently the scheduler uses lists to store the running, waiting and swapped requests.
When iterating over each state queue we pop the first item and append to a new list, which is not good for performance since each pop is O(N) time complexity, which means the scheduler currently runs in O(N^2) time complexity (a pop happens for each item in the state queue).
Instead of using lists we could use deques, since we can pop the first item from a deque in O(1) time complexity, making the scheduler run in O(N) time complexity instead of O(N^2).
I wasn't sure whether I should keep the same types in the SchedulerOutputs class and cast from a deque to a list before returning the result, but since it seems to work with the SchedulerOutputs contains deques instead of lists I decided to change the types.