[jira] [Updated] (KAFKA-938) High CPU usage when more or less idle

["Sam Meder (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/KAFKA-938?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Sam Meder updated KAFKA-938:
----------------------------

    Status: Patch Available  (was: Open)
    
> High CPU usage when more or less idle
> -------------------------------------
>
>                 Key: KAFKA-938
>                 URL: https://issues.apache.org/jira/browse/KAFKA-938
>             Project: Kafka
>          Issue Type: Bug
>          Components: core
>    Affects Versions: 0.8
>            Reporter: Sam Meder
>            Priority: Critical
>             Fix For: 0.8
>
>         Attachments: timeunit.patch
>
>
> We've noticed Kafka using a lot of CPU in a pretty much idle environment and tracked it down to it's DelayedItem implementation. In particular, the time conversion for how much longer to wait:
>   def getDelay(unit: TimeUnit): Long = {
>     val elapsedMs = (SystemTime.milliseconds - createdMs)
>     unit.convert(max(delayMs - elapsedMs, 0), unit)
>   }
> does not actually convert, so Kafka ends up treating a ms value like nanoseconds, e.g. waking up every 100 ns or so. The above code should really be:
>   def getDelay(unit: TimeUnit): Long = {
>     val elapsedMs = (SystemTime.milliseconds - createdMs)
>     unit.convert(max(delayMs - elapsedMs, 0), TimeUnit.MILLISECONDS)
>   }
> I'll attach a patch.

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