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https://issues.apache.org/jira/browse/HBASE-14331?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14966569#comment-14966569
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Hiroshi Ikeda commented on HBASE-14331:
---------------------------------------

I have realized I can create a series of small patches:

1. Fix bugs about RWQueueRpcExecutor.
2. Use a high-scale counter for a frequently accessed counter in RpcExecutor.
3. Introduce CallQueue and make RpcExecutor use it.
4. Introduce CallQueueFacotry and introduce alternative RPC executors.
5. Avoid calculating the deadline value each time.
6. Introduce semaphore based implementation classes of CallQueue.

But some patches are still not so trivial despite the separation...
Is that meaningful to create sub tasks?

> a single callQueue related improvements
> ---------------------------------------
>
>                 Key: HBASE-14331
>                 URL: https://issues.apache.org/jira/browse/HBASE-14331
>             Project: HBase
>          Issue Type: Improvement
>          Components: IPC/RPC, Performance
>            Reporter: Hiroshi Ikeda
>            Assignee: Hiroshi Ikeda
>            Priority: Minor
>         Attachments: BlockingQueuesPerformanceTestApp-output.pdf, 
> BlockingQueuesPerformanceTestApp-output.txt, 
> BlockingQueuesPerformanceTestApp.java, CallQueuePerformanceTestApp.java, 
> HBASE-14331-V2.patch, HBASE-14331-V3.patch, HBASE-14331-V4.patch, 
> HBASE-14331-V5.patch, HBASE-14331-V6.patch, HBASE-14331-V6.patch, 
> HBASE-14331.patch, HBASE-14331.patch, SemaphoreBasedBlockingQueue.java, 
> SemaphoreBasedLinkedBlockingQueue.java, 
> SemaphoreBasedPriorityBlockingQueue.java
>
>
> {{LinkedBlockingQueue}} well separates locks between the {{take}} method and 
> the {{put}} method, but not between takers, and not between putters. These 
> methods are implemented to take locks at the almost beginning of their logic. 
> HBASE-11355 introduces multiple call-queues to reduce such possible 
> congestion, but I doubt that it is required to stick to {{BlockingQueue}}.
> There are the other shortcomings of using {{BlockingQueue}}. When using 
> multiple queues, since {{BlockingQueue}} blocks threads it is required to 
> prepare enough threads for each queue. It is possible that there is a queue 
> starving for threads while there is another queue where threads are idle. 
> Even if you can tune parameters to avoid such situations, the tuning is not 
> so trivial.
> I suggest using a single {{ConcurrentLinkedQueue}} with {{Semaphore}}.



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