Wei-Chiu Chuang commented on HADOOP-15598:

LGTM. Linked HADOOP-12925 to this jira. From git blame this looks like what 
caused it.

Reset priority to major. This is at least a major-level issue.

I did a quick search of "System.property" in the codebase, and most usage are 
for static variables or in the initialization method. +1 to have a follow up 
Jira to cover similar usage, if Steve agrees.

> DataChecksum calculate checksum is contented on hashtable synchronization
> -------------------------------------------------------------------------
>                 Key: HADOOP-15598
>                 URL: https://issues.apache.org/jira/browse/HADOOP-15598
>             Project: Hadoop Common
>          Issue Type: Improvement
>          Components: common
>    Affects Versions: 3.2.0, 3.1.1
>            Reporter: Prasanth Jayachandran
>            Assignee: Prasanth Jayachandran
>            Priority: Major
>         Attachments: HADOOP-15598.1.patch, HADOOP-15598.1.patch, Screen Shot 
> 2018-07-11 at 1.45.06 AM.png, Screen Shot 2018-07-11 at 2.01.54 AM.png
> When profiling a multi-threaded hive streaming ingest, observed lock 
> contention on java.util.Properties getProperty() to check if os is "sparc". 
> java.util.Properties internally uses HashTable. HashTable.get() is 
> synchronized method. In the test application, on a 30s profile with 64 
> threads ~40% CPU time is spent on getProperty() contention. See attached 
> snapshot.

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