NAME
forkoff
SYNOPSIS
brain-dead simple parallel processing for ruby
URI
http://rubyforge.org/projects/codeforpeople
INSTALL
gem install forkoff
DESCRIPTION
forkoff works for any enumerable object, iterating a code block to run in a
child process and collecting the results. forkoff can limit the number of
child processes which is, by default, 2.
HISTORY
0.0.4
- code re-org
- add :strategy option
- default number of processes is 2, not 8
SAMPLES
<========< samples/a.rb >========>
~ > cat samples/a.rb
# forkoff makes it trivial to do parallel processing with ruby, the following
# prints out each word in a separate process
···
#
require 'forkoff'
%w( hey you ).forkoff!{|word| puts "#{ word } from #{ Process.pid }"}
~ > ruby samples/a.rb
hey from 1032
you from 1033
<========< samples/b.rb >========>
~ > cat samples/b.rb
# for example, this takes only 4 seconds or so to complete (8 iterations
# running in two processes = twice as fast)
#
require 'forkoff'
a = Time.now.to_f
results =
(0..7).forkoff do |i|
sleep 1
i ** 2
end
b = Time.now.to_f
elapsed = b - a
puts "elapsed: #{ elapsed }"
puts "results: #{ results.inspect }"
~ > ruby samples/b.rb
elapsed: 4.25545883178711
results: [0, 1, 4, 9, 16, 25, 36, 49]
<========< samples/c.rb >========>
~ > cat samples/c.rb
# forkoff does *NOT* spawn processes in batches, waiting for each batch to
# complete. rather, it keeps a certain number of processes busy until all
# results have been gathered. in otherwords the following will ensure that 3
# processes are running at all times, until the list is complete. note that
# the following will take about 3 seconds to run (3 sets of 3 @ 1 second).
#
require 'forkoff'
pid = Process.pid
a = Time.now.to_f
pstrees =
%w( a b c d e f g h i ).forkoff! :processes => 3 do |letter|
sleep 1
{ letter => ` pstree -l 2 #{ pid } ` }
end
b = Time.now.to_f
puts
puts "pid: #{ pid }"
puts "elapsed: #{ b - a }"
puts
require 'yaml'
pstrees.each do |pstree|
y pstree
end
~ > ruby samples/c.rb
pid: 1048
elapsed: 3.14415812492371
---
a: |
-+- 01048 ahoward ruby -Ilib samples/c.rb
>-+- 01049 ahoward ruby -Ilib samples/c.rb
>-+- 01050 ahoward ruby -Ilib samples/c.rb
\-+- 01051 ahoward ruby -Ilib samples/c.rb
---
b: |
-+- 01048 ahoward ruby -Ilib samples/c.rb
>-+- 01049 ahoward (ruby)
>-+- 01050 ahoward ruby -Ilib samples/c.rb
\-+- 01051 ahoward ruby -Ilib samples/c.rb
---
c: |
-+- 01048 ahoward ruby -Ilib samples/c.rb
>-+- 01049 ahoward ruby -Ilib samples/c.rb
>-+- 01050 ahoward ruby -Ilib samples/c.rb
\-+- 01051 ahoward ruby -Ilib samples/c.rb
---
d: |
-+- 01048 ahoward ruby -Ilib samples/c.rb
>-+- 01061 ahoward ruby -Ilib samples/c.rb
>-+- 01062 ahoward ruby -Ilib samples/c.rb
\-+- 01063 ahoward ruby -Ilib samples/c.rb
---
e: |
-+- 01048 ahoward ruby -Ilib samples/c.rb
>-+- 01061 ahoward (ruby)
>-+- 01062 ahoward ruby -Ilib samples/c.rb
\-+- 01063 ahoward ruby -Ilib samples/c.rb
---
f: |
-+- 01048 ahoward ruby -Ilib samples/c.rb
>-+- 01061 ahoward ruby -Ilib samples/c.rb
>-+- 01062 ahoward ruby -Ilib samples/c.rb
\-+- 01063 ahoward ruby -Ilib samples/c.rb
---
g: |
-+- 01048 ahoward ruby -Ilib samples/c.rb
>-+- 01090 ahoward ruby -Ilib samples/c.rb
>-+- 01091 ahoward ruby -Ilib samples/c.rb
\-+- 01092 ahoward ruby -Ilib samples/c.rb
---
h: |
-+- 01048 ahoward ruby -Ilib samples/c.rb
>-+- 01090 ahoward ruby -Ilib samples/c.rb
>-+- 01091 ahoward ruby -Ilib samples/c.rb
\-+- 01092 ahoward ruby -Ilib samples/c.rb
---
i: |
-+- 01048 ahoward ruby -Ilib samples/c.rb
>-+- 01090 ahoward ruby -Ilib samples/c.rb
>-+- 01091 ahoward ruby -Ilib samples/c.rb
\-+- 01092 ahoward ruby -Ilib samples/c.rb
<========< samples/d.rb >========>
~ > cat samples/d.rb
# forkoff supports two strategies of reading the result from the child: via
# pipe (the default) or via file. you can select which to use using the
# :strategy option.
#
require 'forkoff'
%w( hey you guys ).forkoff :strategy => :file do |word|
puts "#{ word } from #{ Process.pid }"
end
~ > ruby samples/d.rb
hey from 1102
you from 1103
guys from 1104
a @ http://codeforpeople.com/
--
we can deny everything, except that we have the possibility of being better. simply reflect on that.
h.h. the 14th dalai lama