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  1. Cassandra
  2. CASSANDRA-4718

More-efficient ExecutorService for improved throughput

    Details

    • Type: Improvement
    • Status: Resolved
    • Priority: Minor
    • Resolution: Fixed
    • Fix Version/s: 2.1 rc1
    • Component/s: None
    • Labels:

      Description

      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.)

        Attachments

        1. PerThreadQueue.java
          3 kB
          Vijay
        2. baq vs trunk.png
          44 kB
          Ryan McGuire
        3. op costs of various queues.ods
          28 kB
          Benedict
        4. stress op rate with various queues.ods
          37 kB
          Benedict
        5. v1-stress.out
          11 kB
          Jason Brown
        6. 4718-v1.patch
          23 kB
          Jason Brown
        7. backpressure-stress.out.txt
          13 kB
          Jason Brown
        8. belliotsmith_branches-stress.out.txt
          10 kB
          Jason Brown
        9. aws.svg
          9 kB
          Benedict
        10. jason_read.svg
          8 kB
          Benedict
        11. jason_read_latency.svg
          11 kB
          Benedict
        12. jason_write.svg
          8 kB
          Benedict
        13. aws_read.svg
          8 kB
          Benedict
        14. stress_2014May15.txt
          11 kB
          Jason Brown
        15. stress_2014May16.txt
          10 kB
          Jason Brown
        16. austin_diskbound_read.svg
          12 kB
          Benedict
        17. jason_run1.svg
          7 kB
          Benedict
        18. jason_run2.svg
          7 kB
          Benedict
        19. jason_run3.svg
          7 kB
          Benedict
        20. E10M_summary_key_s.svg
          7 kB
          Benedict
        21. E100M_summary_key_s.svg
          8 kB
          Benedict
        22. E600M_summary_key_s.svg
          8 kB
          Benedict

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              • Assignee:
                benedict Benedict
                Reporter:
                jbellis Jonathan Ellis
                Reviewer:
                Jason Brown
              • Votes:
                2 Vote for this issue
                Watchers:
                33 Start watching this issue

                Dates

                • Created:
                  Updated:
                  Resolved: