[YARN-6682] Improve performance of AssignmentInformation datastructures

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.8.0
• Fix Version/s: 2.9.0, 3.0.0-alpha4, 2.8.2
• Target Version/s: 2.8.2
• Hadoop Flags: Reviewed
• Assignee: Daryn Sharp
• Reporter: Daryn Sharp
• Created: 01/Jun/17 21:09
• Updated: 09/Jun/17 06:33
• Resolved: 09/Jun/17 06:33

Description

AssignmentInformation is inefficient and creates lots of garbage that increase gc pressure. It creates 3 hashmaps that each contain only 2 enum-based keys. This requires wrapper node objects, boxing/unboxing of ints, and more expensive lookups than simply using primitive arrays indexed by enum ordinal.