Improve frequent loops when only one of activities is productive #7679
Conversation
This file contains 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
k8s-ci-robot
added
kind/feature
k8s-ci-robot
added
the
size/XS
k8s-ci-robot
added
the
lgtm
|
/lgtm |
|
[APPROVALNOTIFIER] This PR is APPROVED This pull-request has been approved by: aleksandra-malinowska, macsko The full list of commands accepted by this bot can be found here. The pull request process is described here
Needs approval from an approver in each of these files:
Approvers can indicate their approval by writing |
k8s-ci-robot
added
the
approved
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Outdated suggestions cannot be applied.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 type of PR is this?
/kind feature
What this PR does / why we need it:
In a single iteration of the autoscaler, only one of the activities can occur alternately: scaling up or processing ProvisioningRequests. If the activity is productive (scale up attempt was successful or ProvisioningRequest was processed), the next iteration is started immediately. Unfortunately, if there is only successful processing of ProvisioningRequests without scaling up activity (so if there are only unschedulable pods that CA scale up won't help), the autoscaler will be put to sleep unnecessarily. This PR changes the logic slightly to compare not with the start of the last iteration, but with the previous to the last, to support alternate activities well.
For example, before this PR:
successful provreq processing -> immediate next loop (because provreq was processed) -> scale up attempt with non-successful result -> sleep for scanInterval duration (because scale up attempt was not successful)-> next provreq processing
After:
successful provreq processing -> immediate next loop (because provreq was processed) -> scale up attempt with non-successful result -> immediate next loop (because before the scale up attempt provreq was processed)-> next provreq processing
Which issue(s) this PR fixes:
Fixes #
Special notes for your reviewer:
Does this PR introduce a user-facing change?
Additional documentation e.g., KEPs (Kubernetes Enhancement Proposals), usage docs, etc.: