[rabbitmq-discuss] Fwd: Performance bottleneck on inter-node connection
matthias at rabbitmq.com
Thu Apr 17 14:56:32 BST 2014
On 15/04/14 14:20, joseph rouphael wrote:
> On Mon, Apr 14, 2014 at 12:00 PM, Matthias Radestock
> <matthias at rabbitmq.com <mailto:matthias at rabbitmq.com>> wrote:
> What happens when you run the above test with both nodes on the same
> The result is almost the same: Fluctuating between 10 and 23KHZ
Thanks for running all these tests. I've reproduced your observations.
What we are seeing here is, at least partially, an issue with the Erlang
I noticed that when running the test with PerfTest, single producer,
single consumer, two nodes, the consuming node was using 100% CPU, i.e.
the equivalent of a single core. That is usually an indication of an
Erlang scheduler issue since there is an appreciable degree of
parallelism that should be exploitable.
For this particular test I managed to double performance by supplying
the "+swt very_low" or "+sfwi 1" flags to Erlang via
So these flags, plus the other +s... flags of the Erlang VM, are worth
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