From: John Carter <john.carter@...>
Date: 2008-03-27T04:53:31+09:00
Subject: Re: "loop do IO.select([io], nil, nil)" eats 95% of CPU, any other 	way?

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On Thu, 27 Mar 2008, I=C3=B1aki Baz Castillo wrote:

> Hi, which is the most efficient way of receiving and processing dat=
a
=66rom a network socket?

I use GServer in this common way:

--------------
class MyServer < GServer
     def serve(io)
         loop do
               if IO.select([io], nil, nil)
                   ....
--------------

A "top" says to me that Ruby is eating more than 90% of CPU and there
is no connections yet... :(
Any other suggestion?


Hmm.From the "man select" page...

       timeout is an upper bound on the amount of time elapsed before
        select() returns.  It may be zero, causing select() to return
        immediately.  (This is useful for polling.)  If timeout is NU=
LL
        (no timeout), select() can block indefinitely.

ri IO.select
  IO.select(read_array
      [, write_array
      [, error_array
      [, timeout]]] ) =3D>  array  or  nil

My guess is you have one too few nil's in there and the default timeo=
ut is 0 not nil.

If you are on linux say...

   "man strace"

to discover why linux is such a great place to develop on.... you can
_always_ find out what is really going on with any program.

As a little side comment...  You can _always_ take a program written
around a select & state machine and make it multi-threaded doing
blocking I/O or conversely refactor a multi-threaded app into a selec=
t
based state machine.

Choose whichever is easiest / cleanest for you.


John Carter                             Phone : (64)(3) 358 6639
Tait Electronics                        Fax   : (64)(3) 359 4632
PO Box 1645 Christchurch                Email : john.carter@tait.co.n=
z
New Zealand

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