From: "Ara.T.Howard" <Ara.T.Howard@...>
Date: 2005-10-16T15:48:53+09:00
Subject: Re: Help! define_method leaking procs...

On Sun, 16 Oct 2005, Ara.T.Howard wrote:

> this is quite suspect:
>
> [ahoward@localhost ~]$ for i in $(seq 0 18);do
>  printf "$i => ";
>  ruby -e' class << self; (2**ARGV.shift.to_i).times{|n| s = '42' * n; 
> define_method("f#{ n }"){ 42 }}; end; GC::start; p IO::read("/proc/#{ $$ 
> }/status").grep(/VmSize/) ' $i;
> done
>
> 0 => ["VmSize:\t    2840 kB\n"]
> 1 => ["VmSize:\t    2840 kB\n"]
> 2 => ["VmSize:\t    2840 kB\n"]
> 3 => ["VmSize:\t    2840 kB\n"]
> 4 => ["VmSize:\t    2844 kB\n"]
> 5 => ["VmSize:\t    2840 kB\n"]
> 6 => ["VmSize:\t    2840 kB\n"]
> 7 => ["VmSize:\t    2844 kB\n"]
> 8 => ["VmSize:\t    2976 kB\n"]
> 9 => ["VmSize:\t    3456 kB\n"]
> 10 => ["VmSize:\t    3720 kB\n"]
> 11 => ["VmSize:\t    4380 kB\n"]
> 12 => ["VmSize:\t    6072 kB\n"]
> 13 => ["VmSize:\t    9456 kB\n"]
> 14 => ["VmSize:\t   15996 kB\n"]
> 15 => ["VmSize:\t   28704 kB\n"]
> 16 => ["VmSize:\t   53352 kB\n"]
> 17 => ["VmSize:\t  101220 kB\n"]
> 18 => ["VmSize:\t  194404 kB\n"]
>
>
> note the progression is linear until 13 (note irony) and then climbs
> exponentially - doubling each time.

and even wrapping in a method doesn't seem to help

   [ahoward@localhost ~]$ ruby a.rb 15
          1 => VmSize:         2844 kB
          2 => VmSize:         2848 kB
          4 => VmSize:         2848 kB
          8 => VmSize:         2848 kB
         16 => VmSize:         2848 kB
         32 => VmSize:         2848 kB
         64 => VmSize:         2976 kB
        128 => VmSize:         3108 kB
        256 => VmSize:         3724 kB
        512 => VmSize:         4648 kB
       1024 => VmSize:         5572 kB
       2048 => VmSize:         9904 kB
       4096 => VmSize:        13104 kB
       8192 => VmSize:        27016 kB
      16384 => VmSize:        46676 kB


   [ahoward@localhost ~]$ cat a.rb
   class Object
     def gen_method
       klass = Class === self ? self : self.class
       class << klass
         define_method("f#{ rand(2 ** 42) }"){ 42 }
       end
     end
   end

   limit = Integer ARGV.shift

   limit.times do |l|
     n = 2 ** l

     n.times{|i| s = '42' * i and gen_method}

     GC::start

     printf "% 8d => %s", n, IO::read("/proc/#{ $$ }/status").grep(/VmSize/)
   end

still exponential after a threshold...

-a
-- 
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| email :: ara [dot] t [dot] howard [at] noaa [dot] gov
| phone :: 303.497.6469
| anything that contradicts experience and logic should be abandoned.
| -- h.h. the 14th dalai lama
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