[HADOOP-5664] Use of ReentrantLock.lock() in MapOutputBuffer takes up too much cpu time

• Type: Improvement
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 0.19.1
• Fix Version/s: 0.21.0
• Hadoop Flags: Reviewed
• Assignee: Christopher Douglas
• Reporter: Bryan Duxbury
• Created: 13/Apr/09 20:59
• Updated: 22/Mar/18 14:30
• Resolved: 29/May/09 00:58

Description

In examining a profile of one of my mappers today, I noticed that the method ReentrantLock.lock() in MapTask$MapOutputBuffer seems to be taking up ~11 seconds out of around 100 seconds total. It seems like 10% is an awfully large amount of time to spend in this lock.

Issue Links

• is duplicated by: HADOOP-6672 BytesWritable.write(buf) use much more CPU in writeInt() then write(buf)