[erlang-questions] +secio emulator flag

Michael Truog <>
Tue Sep 12 19:49:13 CEST 2017

On 09/12/2017 10:23 AM, Mikael Karlsson wrote:
> Thanks Lukas and Michael,
>> (sorry for the late reply, I meant to reply to this before but forgot)
> No problem, maybe your personal secio flag also was set to true and
> something else came in between :-) .
> The use case I have here is a single (tcp) connection with high load.
> I think that there are other bottlenecks with this scenario since one
> can only attach one scheduler/erlang process to this, if I understand
> it right, but nevertheless would setting secio to false give the
> attached erlang process more time to finish the work in this case?

My impression is that secio set to true will help if you really do have lots of throughput coming through some number of Erlang ports (sockets or other file descriptors), though it may reduce the performance of Erlang source code that doesn't need to use Erlang ports, so, heavy use of an Erlang process that benefits from spending as much time on a scheduler as possible, though that is based on older testing.  The default changed from false to true, so it appears that most use should benefit from keeping it set to true.  Ideally, you could loadtest with the setting set either way, to see which is best for your use-case.

Best Regards,

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