[HADOOP-10279] Create multiplexer, a requirement for the fair queue

• Type: Sub-task
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 2.5.0
• Hadoop Flags: Reviewed
• Assignee: Chris Li
• Reporter: Chris Li
• Created: 25/Jan/14 03:18
• Updated: 04/Sep/14 00:36
• Resolved: 20/Jun/14 09:55

Description

The Multiplexer helps the FairCallQueue decide which of its internal sub-queues to read from during a poll() or take(). It controls the penalty of being in a lower queue. Without the mux, the FairCallQueue would have issues with starvation of low-priority requests.

The WeightedRoundRobinMultiplexer is an implementation which uses a weighted round robin approach to muxing the sub-queues. It is configured with an integer list pattern.

For example: 10, 5, 5, 2 means:

• Read queue 0 10 times
• Read queue 1 5 times
• Read queue 2 5 times
• Read queue 3 2 times
• Repeat

Issue Links

• is depended upon by: HADOOP-10282 Create a FairCallQueue: a multi-level call queue which schedules incoming calls and multiplexes outgoing calls