From: Steven Lumos <steven@...>
Date: 2007-08-08T06:26:36+09:00
Subject: Re: [ANN] Free RAM 1.0

Alex Gutteridge <alexg@kuicr.kyoto-u.ac.jp> writes:

> On 7 Aug 2007, at 07:06, Ari Brown wrote:
>
>> Hey!
>>
>> Despite your best efforts, Todd, I managed to create a tool which
>> will free RAM to be used by other programs.
>>
>> At the moment, it is only usable on *nix machines (BSD, Linux, and
>> Mac). Will add Windows support soon.
>> move it to /bin and save it as free_ram
>>
>> Usage: free_ram TIME
>> TIME is the amount of time you want Ruby to spend clearing the RAM.
>> A good amount is about 20. I can clear a large amount of RAM with
>> that.
>>
>> http://www.aribrown.com/ruby/free_ram.rb
>
> Other people have explained why this really isn't such a great idea,
> but in the spirit of experimentation...
>
> If you want a portable version why not just:
>
> require 'timeout'
>
> z = ''
> timeout(25){ while(true) do z << 0.chr * (2 ** 24) end}
>
> Or for the 'moar power!!11!' user how about a RubyInline version:
>
> require 'inline'
>
> class IWantA
>   inline do |builder|
>     builder.c "
>     int way_to_die(int size){
>       return malloc(size);
>     }"
>   end
> end
>
> while(IWantA.new.way_to_die(2 ** 12) != 0)
> end
>
> Both managed to shunt almost every other process into swap in a few
> seconds. Enjoy!
>
> Alex Gutteridge
>
> Bioinformatics Center
> Kyoto University

Back in the day, a fellow geek CS undergrad came up with something like:

int main(int argc, char** argv)
{
  size_t n = 1;
  while (n > 0) {
    if (malloc(n))
      n <<= 1;
    else 
      n >>= 1;
  }
}

Steve