[ANN] forkoff-1.1.0

[ara.t.howard]

NAME

forkoff

SYNOPSIS

brain-dead simple parallel processing for ruby

URI

http://rubyforge.org/projects/codeforpeople
http://github.com/ahoward/forkoff

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.

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 7907
you from 7908


<========< 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: 4.19184589385986
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! rocesses => 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: 7922
elapsed: 3.37899208068848

---
a: |
-+- 07922 ahoward ruby -Ilib samples/c.rb
|-+- 07923 ahoward ruby -Ilib samples/c.rb
|-+- 07924 ahoward (ruby)
\-+- 07925 ahoward ruby -Ilib samples/c.rb

---
b: |
-+- 07922 ahoward ruby -Ilib samples/c.rb
|-+- 07923 ahoward ruby -Ilib samples/c.rb
|-+- 07924 ahoward ruby -Ilib samples/c.rb
\-+- 07925 ahoward ruby -Ilib samples/c.rb

---
c: |
-+- 07922 ahoward ruby -Ilib samples/c.rb
|-+- 07923 ahoward ruby -Ilib samples/c.rb
|-+- 07924 ahoward (ruby)
\-+- 07925 ahoward ruby -Ilib samples/c.rb

---
d: |
-+- 07922 ahoward ruby -Ilib samples/c.rb
|-+- 07932 ahoward ruby -Ilib samples/c.rb
|--- 07933 ahoward ruby -Ilib samples/c.rb
\--- 07934 ahoward ruby -Ilib samples/c.rb

---
e: |
-+- 07922 ahoward ruby -Ilib samples/c.rb
|--- 07932 ahoward (ruby)
|-+- 07933 ahoward ruby -Ilib samples/c.rb
\-+- 07934 ahoward (ruby)

---
f: |
-+- 07922 ahoward ruby -Ilib samples/c.rb
|--- 07932 ahoward (ruby)
|-+- 07933 ahoward ruby -Ilib samples/c.rb
\-+- 07934 ahoward ruby -Ilib samples/c.rb

---
g: |
-+- 07922 ahoward ruby -Ilib samples/c.rb
|-+- 07941 ahoward ruby -Ilib samples/c.rb
|--- 07942 ahoward ruby -Ilib samples/c.rb
\--- 07943 ahoward ruby -Ilib samples/c.rb

---
h: |
-+- 07922 ahoward ruby -Ilib samples/c.rb
|-+- 07941 ahoward (ruby)
|-+- 07942 ahoward ruby -Ilib samples/c.rb
\--- 07943 ahoward ruby -Ilib samples/c.rb

---
i: |
-+- 07922 ahoward ruby -Ilib samples/c.rb
|--- 07942 ahoward (ruby)
\-+- 07943 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 7953
you from 7954
guys from 7955



HISTORY
1.1.0
- move to a model with one work queue and signals sent from
consumers to
producer to noitify ready state. this let's smaller jobs race
through a
single process even while a larger job may have one sub-process
bound up.
incorporates a fix from http://github.com/fredrikj/forkoff which
meant
some processes would lag behind when jobs didn't have similar
execution
times.

1.0.0
- move to github

0.0.4
- code re-org
- add :strategy option
- default number of processes is 2, not 8

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( rocesses => 2 ) ...

or plain vanilla number

forkoff( 2 ) ...

to the forkoff call

- default number of processes is 8, not 2


0.0.0

initial version


enjoy.