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Hiroshi Ikeda commented on HBASE-14479: --------------------------------------- That's interesting. I don't know details about YCSB, but does it use multiple connections? The selectors without the patch consume more CPU time than the selector with the patch. Park/unpark in the semaphore with the patch consumes non-trivial CPU time. The semaphore releases a permit for each connection to read, but there might be actually well context switches to wake up threads with overhead of park/unpark compared to cost of their tasks. > Apply the Leader/Followers pattern to RpcServer's Reader > -------------------------------------------------------- > > Key: HBASE-14479 > URL: https://issues.apache.org/jira/browse/HBASE-14479 > Project: HBase > Issue Type: Improvement > Components: IPC/RPC, Performance > Reporter: Hiroshi Ikeda > Assignee: Hiroshi Ikeda > Priority: Minor > Attachments: HBASE-14479-V2 (1).patch, HBASE-14479-V2.patch, > HBASE-14479-V2.patch, HBASE-14479.patch, flamegraph-19152.svg, > flamegraph-32667.svg, gc.png, gets.png, io.png, median.png > > > {{RpcServer}} uses multiple selectors to read data for load distribution, but > the distribution is just done by round-robin. It is uncertain, especially for > long run, whether load is equally divided and resources are used without > being wasted. > Moreover, multiple selectors may cause excessive context switches which give > priority to low latency (while we just add the requests to queues), and it is > possible to reduce throughput of the whole server. -- This message was sent by Atlassian JIRA (v6.3.4#6332)