[rabbitmq-discuss] rabbitmq cpu usage can not be more than 700%

[Simon MacMullen]

Just to follow up - Xie told me that an upgrade to R16B got them to 
2300% utilisation.

Cheers, Simon

On 12/03/13 17:36, Jesper Louis Andersen wrote:
> It is due to the way Erlang spins up more cores. The Erlang VM decides
> at certain intervals how many cores it needs to satisfy the work it has.
> If it never needs more than 7 cores to satisfy work, it will never spin
> up more. Also note that it will keep a core "awake" even if there is no
> work to do in the hope that work will arrive soon. So you cannot use a
> command like top(1) to get any idea of what is happening.
>
> The way is to get a shell on an erlang node and then use
>
> http://erlang.org/doc/man/erlang.html#statistics-1
>
> in particular the scheduler_wall_time stats to get a grip on scheduler
> utilization.
>
> My guess would be that you are bound by something else than CPU.
>
>
> On Thu, Mar 7, 2013 at 9:14 AM, Xie Yunpeng <woqimingweipeng at gmail.com
> <mailto:woqimingweipeng at gmail.com>> wrote:
>
>     rabbitmq version: 3.0.2
>     cpu: 24 cores
>     memory: 64G
>     i deploy a rabbitmq service on the server above and do a stress
>     testing , use 150 threads for send and 300 threads for recv on 150
>     queues on the service, per queue with 1 send/ 2 recv.
>     the cpu useage is always below 700%, no matter i increase queues and
>     threads or not.
>
>     how to use more than 7 cores in rabbitmq?
>
>     i find smp is set to 24:24
>     [rabbitmq]$ erl
>     Erlang R15B03 (erts-5.9.3.1) [source] [64-bit] [smp:24:24]
>     [async-threads:0] [hipe] [kernel-poll:false]
>
>     Eshell V5.9.3.1  (abort with ^G)
>
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>
> --
> J.
>
>
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-- 
Simon MacMullen
RabbitMQ, VMware