[HDFS-15975] Use LongAdder instead of AtomicLong

• Type: Wish
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.3.1, 3.4.0
• Fix Version/s: 3.3.1, 3.4.0
• Component/s: metrics
• Labels: pull-request-available
• Target Version/s: 3.3.1, 3.4.0
• Hadoop Flags: Reviewed
• Release Note: This JIRA changes public fields in DFSHedgedReadMetrics. If you are using the public member variables of DFSHedgedReadMetrics, you need to use them through the public API.
• Assignee: Tao Li
• Reporter: Tao Li
• Created: 14/Apr/21 14:27
• Updated: 12/Feb/24 06:56
• Resolved: 17/Apr/21 07:50

Description

When counting some indicators, we can use LongAdder instead of AtomicLong to improve performance. The long value is not an atomic snapshot in LongAdder, but I think we can tolerate that.

Issue Links

• relates to: HADOOP-17671 Run jacc to check for Hadoop's Java API compat
• links to: GitHub Pull Request #2907
• links to: GitHub Pull Request #2930
• links to: GitHub Pull Request #2936
• links to: GitHub Pull Request #2940