[erlang-questions] : Subtle behaviour of Erlang scheduler
Mon May 28 21:15:48 CEST 2007
Kenneth Lundin wrote:
> It is important that we make clear in the documentation how priorities work and
> that you have little or no reason to use them.
> I hope we can close this discussion now.
We can close the discussion, if you want, but IMHO it's quite strange to
say, in an official documentation, that a feature is present but there's
no reason to use it. A normal question, in this case, could be: why to
not remove the feature, if it's useless?
In any case, I think that it's extermely rare to use Erlang for a
CPU-bound computation like the simple code we posted. As far as I know,
an Erlang program is made of many processes that exchange messages and
use few CPU to process such messages. So the situation we experienced
should never happen.
But this does not mean that, in my opinion, the Erlang priority system
has a serious flaw and should be rethought. Probably, in a
telecommunication system, priorities could not be so important, but if
you use Erlang in real-time embedded environment (and it's argued that
Erlang is for soft-real-time systems), such as automation or even
robotics (and this is our application field), priorities are
fundamental, together with correct or predictable behaviour of the
Unless we want to exclude Erlang from some *very interesting*
All the best,
Eng. Corrado Santoro, Ph.D.
University of Catania - ITALY - Engineering Faculty
Tel: +39 095 7382380 VoIP: sip:
Personal Home Page: http://www.diit.unict.it/users/csanto
NUXI Home Page: http://nuxi.diit.unict.it
More information about the erlang-questions