NAME
forkoff
SYNOPSIS
brain-dead simple parallel processing for ruby
URI
http://rubyforge.org/projects/codeforpeople
INSTALL
gem install forkoff
HISTORY
0.0.1
-
updated to use producer threds pushing onto a SizedQueue for each
consumer
channel. in this way the producers do not build up a massize
parllel data
structure but provide data to the consumers only as fast as they
can fork
and proccess it. basically for a 4 process run you’ll end up
with 4
channels of size 1 between 4 produces and 4 consumers, each
consumer is a
thread popping of jobs, forking, and yielding results. -
removed use of Queue for capturing the output. now it’s simply
an array
of arrays which removed some sync overhead. -
you can configure the number of processes globally with
Forkoff.default[‘proccess’] = 4
-
you can now pass either an options hash
forkoff( :processes => 2 ) …
or plain vanilla number
forkoff( 2 ) …
to the forkoff call
-
default number of processes is 2, not 8
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.
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 19511
you from 19512
<========< 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: 4.19796895980835
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: 19526
elapsed: 3.39831399917603
---
a: |
-+- 19526 ahoward ruby -Ilib samples/c.rb
|-+- 19527 ahoward ruby -Ilib samples/c.rb
|-+- 19528 ahoward ruby -Ilib samples/c.rb
\-+- 19529 ahoward ruby -Ilib samples/c.rb
---
b: |
-+- 19526 ahoward ruby -Ilib samples/c.rb
|-+- 19527 ahoward ruby -Ilib samples/c.rb
|-+- 19528 ahoward ruby -Ilib samples/c.rb
\-+- 19529 ahoward ruby -Ilib samples/c.rb
---
c: |
-+- 19526 ahoward ruby -Ilib samples/c.rb
|-+- 19527 ahoward (ruby)
|-+- 19528 ahoward (ruby)
\-+- 19529 ahoward ruby -Ilib samples/c.rb
---
d: |
-+- 19526 ahoward ruby -Ilib samples/c.rb
|-+- 19536 ahoward ruby -Ilib samples/c.rb
|-+- 19537 ahoward (ruby)
\--- 19538 ahoward ruby -Ilib samples/c.rb
---
e: |
-+- 19526 ahoward ruby -Ilib samples/c.rb
|-+- 19536 ahoward ruby -Ilib samples/c.rb
|-+- 19537 ahoward ruby -Ilib samples/c.rb
\--- 19538 ahoward ruby -Ilib samples/c.rb
---
f: |
-+- 19526 ahoward ruby -Ilib samples/c.rb
|--- 19536 ahoward (ruby)
|-+- 19538 ahoward ruby -Ilib samples/c.rb
\--- 19543 ahoward ruby -Ilib samples/c.rb
---
g: |
-+- 19526 ahoward ruby -Ilib samples/c.rb
|--- 19543 ahoward (ruby)
|-+- 19546 ahoward ruby -Ilib samples/c.rb
\--- 19547 ahoward ruby -Ilib samples/c.rb
---
h: |
-+- 19526 ahoward ruby -Ilib samples/c.rb
|-+- 19543 ahoward ruby -Ilib samples/c.rb
|--- 19546 ahoward ruby -Ilib samples/c.rb
\--- 19547 ahoward ruby -Ilib samples/c.rb
---
i: |
-+- 19526 ahoward ruby -Ilib samples/c.rb
|-+- 19543 ahoward ruby -Ilib samples/c.rb
|-+- 19546 ahoward ruby -Ilib samples/c.rb
\-+- 19547 ahoward ruby -Ilib samples/c.rb