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Benedict commented on CASSANDRA-4718: ------------------------------------- [~jasobrown] I've updated the repository with a number of minor tweaks/refactors, and improved comments. Let me know if there's anything still unclear. > More-efficient ExecutorService for improved throughput > ------------------------------------------------------ > > Key: CASSANDRA-4718 > URL: https://issues.apache.org/jira/browse/CASSANDRA-4718 > Project: Cassandra > Issue Type: Improvement > Reporter: Jonathan Ellis > Assignee: Jason Brown > Priority: Minor > Labels: performance > Fix For: 2.1.0 > > Attachments: 4718-v1.patch, PerThreadQueue.java, aws.svg, > backpressure-stress.out.txt, baq vs trunk.png, > belliotsmith_branches-stress.out.txt, jason_read.svg, jason_read_latency.svg, > jason_write.svg, op costs of various queues.ods, stress op rate with various > queues.ods, v1-stress.out > > > Currently all our execution stages dequeue tasks one at a time. This can > result in contention between producers and consumers (although we do our best > to minimize this by using LinkedBlockingQueue). > One approach to mitigating this would be to make consumer threads do more > work in "bulk" instead of just one task per dequeue. (Producer threads tend > to be single-task oriented by nature, so I don't see an equivalent > opportunity there.) > BlockingQueue has a drainTo(collection, int) method that would be perfect for > this. However, no ExecutorService in the jdk supports using drainTo, nor > could I google one. > What I would like to do here is create just such a beast and wire it into (at > least) the write and read stages. (Other possible candidates for such an > optimization, such as the CommitLog and OutboundTCPConnection, are not > ExecutorService-based and will need to be one-offs.) > AbstractExecutorService may be useful. The implementations of > ICommitLogExecutorService may also be useful. (Despite the name these are not > actual ExecutorServices, although they share the most important properties of > one.) -- This message was sent by Atlassian JIRA (v6.2#6252)