[CASSANDRA-15798] Only calculate 1.0 + dynamicBadnessThreshold once per loop in DynamicEndpointSnitch

• Type: Bug
• Status: Resolved
• Priority: Normal
• Resolution: Fixed
• Fix Version/s: 4.0-beta1, 4.0
• Component/s: Messaging/Internode
• Bug Category: Degradation - Performance Bug/Regression
• Severity: Low
• Complexity: Low Hanging Fruit
• Discovered By: User Report
• Platform: All
• Since Version: 4.0-alpha

Source Control Link

https://github.com/apache/cassandra/commit/66eae58cd4f53c03ca5ab6b520aa490f7f61a59c

Test and Documentation Plan

https://app.circleci.com/pipelines/github/jrwest/cassandra/14/workflows/acf26d1e-7920-4338-b385-f2eb3164e772

• Assignee: Jordan West
• Reporter: Jordan West

Authors

Jordan West

Reviewers

David Capwell

• Created: 08/May/20 00:52
• Updated: 21/Dec/20 08:07
• Resolved: 08/May/20 16:59

Description

The change to make dynamicBadnessThreshold volatile and mutable in https://issues.apache.org/jira/browse/CASSANDRA-12179 could have minor implications for the performance of this code: https://github.com/apache/cassandra/blob/trunk/src/java/org/apache/cassandra/locator/DynamicEndpointSnitch.java#L216. Its better to calculate this once before the loop starts, which has the added benefit that the value is stable throughout the calculation as well.

Issue Links

• links to: Pull Request