Details

    • Type: Sub-task
    • Status: Resolved
    • Priority: Major
    • Resolution: Cannot Reproduce
    • Affects Version/s: None
    • Fix Version/s: None
    • Component/s: None
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      Description

      If Q1 TPCH is run 10 times in a row on the same cluster, with IO elevator,the perf stays relatively consistent (or improves due to JIT and stuff). Without, there's a large perf dip in the middle (usually dag #3 or so for me), then recovery.
      This dip is not caused directly by GC time, and at least in my case I cannot see any particular part becoming slower in YK profiles, or any obvious correlates. One can easily see tasks slow down from 3-7 to 10-30 seconds (up to 60 with slow HDFS reads). One thing that happens is that kernel CPU time goes up to 9-12% on all the daemons when the slowdown is "ramping up" and occuring, compared to usual 0-3% levels. I didn't investigate much where that comes from since this is not a mainline scenario.
      Still, interesting to learn what causes this.
      YK dumps provided upon request.

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              • Assignee:
                Unassigned
                Reporter:
                sershe Sergey Shelukhin
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