[rabbitmq-discuss] RabbitMQ / Erlang not running on all cores?

Tue Oct 22 22:55:00 BST 2013

Matt,

On 22/10/13 22:31, Matt Pietrek wrote:
> Thanks Zhibo. We actually have hundreds of queues. Two of them are
> processing several hundred messages/second. The remaining queues are
> processing 1 or 2 messages second.

Could be an Erlang scheduler thing. Give the latest Erlang release a 
try, since multi-core scheduling is definitely an area that has 
undergone considerable changes in recent releases.

Also, try running

  rabbitmqctl eval 'erlang:statistics(run_queue).'

if this is >0 then there are runnable processes waiting for execution, 
which would indicate some scheduler anomaly.

Matthias.