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This is an automatically generated e-mail. To reply, visit:
https://reviews.apache.org/r/40668/
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Review request for Ambari, Alejandro Fernandez, Nate Cole, and Sid Wagle.
Bugs: AMBARI-14050
https://issues.apache.org/jira/browse/AMBARI-14050
Repository: ambari
Description
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Ambari's default Jetty thread pool is configured at 25 threads. When deployed
on a machine that has 48 "processors", Jetty's calculation for determining how
many "Acceptor" and "Selector" threads to create never takes into account the
core pool size. As a result, we get:
- 12 "Acceptor" threads (these answer binds to port 8080)
- 12 "Selector" threads (these pick available threads to answer bindings)
- 1 free thread (these are the threads available to do stuff with)
Notice that there's only 1 free thread. This means that Jetty effectively makes
Ambari a single-threaded web application on larger systems!
The "fix" is to increase the thread count in the {{ambari.properties}}, however
nobody knows to do this since no warning is produced.
I suggest:
- Log a warning on server startup if we detect that the core pool size is less
than 3/4 of the available processors on the system.
- Automatically increase the core pool size to the min(100, double existing
size) when the above is detected
Diffs
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ambari-server/src/main/java/org/apache/ambari/server/controller/AmbariServer.java
56034d9
ambari-server/src/test/java/org/apache/ambari/server/controller/AmbariServerTest.java
621010a
Diff: https://reviews.apache.org/r/40668/diff/
Testing
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mvn clean test
(thread dumps with simulated Runtime.getRuntime() calls)
Thanks,
Jonathan Hurley
