Chengxiang Li created HDFS-5276:
-----------------------------------
Summary: FileSystem.Statistics got performance issue on
multi-thread read/write.
Key: HDFS-5276
URL: https://issues.apache.org/jira/browse/HDFS-5276
Project: Hadoop HDFS
Issue Type: Bug
Affects Versions: 2.0.4-alpha
Reporter: Chengxiang Li
FileSystem.Statistics is a singleton variable for each FS scheme, each
read/write on HDFS would lead to a AutomicLong.getAndAdd(). AutomicLong does
not perform well in multi-threads(let's say more than 30 threads). so it may
cause serious performance issue. during our test profile, 32 threads read data
from HDFS, about 70% cpu time is spent on
FileSystem.Statistics.incrementBytesRead().
--
This message was sent by Atlassian JIRA
(v6.1#6144)
