[KAFKA-938] High CPU usage when more or less idle

• Type: Bug
• Status: Resolved
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 0.8.0
• Fix Version/s: 0.8.0
• Component/s: core
• Assignee: Unassigned
• Reporter: Sam Meder
• Created: 11/Jun/13 21:39
• Updated: 12/Jun/13 18:43
• Resolved: 12/Jun/13 05:44

Description

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.