[HADOOP-13615] Convert uses of AtomicLong for counter metrics to LongAdder

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Duplicate
• Affects Version/s: 3.0.0-alpha1
• Component/s: metrics
• Target Version/s: 3.0.0-alpha2
• Assignee: Unassigned
• Reporter: Andrew Wang
• Created: 14/Sep/16 20:55
• Updated: 21/Oct/16 18:27
• Resolved: 21/Oct/16 18:27

Description

LongAdder (available in JDK8) can provide much better performance than AtomicLong since it uses thread locals under the hood.

We should consider switching over our uses of AtomicLong and friends over to LongAdder.

If we want to target for JDK7, we can also pull in the implementation since it's pure Java (public domain):

http://gee.cs.oswego.edu/cgi-bin/viewcvs.cgi/jsr166/src/jsr166e/LongAdder.java?view=co

Issue Links

• duplicates: HADOOP-13747 Use LongAdder for more efficient metrics tracking