[erlang-questions] erlc speed (or lack thereof), Make and emake

Scott Lystig Fritchie <>
Fri Jan 25 02:29:37 CET 2013


Matthias Lang <> wrote:

ml> Running the script so it does one call to 'erlc' at a time takes
ml> 183s.

Hrm, well, running on a random OpenSolaris virtual machine that I've got
lying around at the moment....

    % time erl -eval "init:stop(0)."
    Erlang R15B01 (erts-5.9.1) [source] [64-bit] [smp:2:2] [async-threads:0]
    [kernel-poll:false] [dtrace]
    
    Eshell V5.9.1  (abort with ^G)
    1> 
    0.12u 0.05s 0:01.29 13.1%

So, almost 1.3 seconds to start up and stop.  Some of that time is
probably related to shutting down.  The rest is probably startup time.
Some fraction of that is probably the same overhead that starting "erlc"
from scratch each time, plus some overhead that "erlc" has that "erl"
doesn't.  Reduce that sum of time, and you'll save a lot of time in your
Makefile recipes.  Plus, that reduction would likely make "escript"
startup times lower, which would also please a lot of the Erlang world
also?

-Scott

P.S. Keeping mouth shut since rebar's automatic parallellization doesn't
seem to interest everyone else in the thread.... :-)




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