parallel_process.rb

require 'parallel'

module Jekyll

  class Site

    def render
      payload = site_payload
      self.posts.zip(Parallel.map(self.posts) {|post|
        post.render(self.layouts, payload)
        [ post.output, post.content ]
      }).each do |post, result|
        post.output = result[0]
        post.content = result[1]
      end

      self.pages.zip(Parallel.map(self.pages) {|page|
        page.render(self.layouts, payload)
        [ page.output, page.content ]
      }).each do |page, result|
        page.output = result[0]
        page.content = result[1]
      end

      self.categories.values.map { |ps| ps.sort! { |a, b| b <=> a } }
      self.tags.values.map { |ps| ps.sort! { |a, b| b <=> a } }
    rescue Errno::ENOENT => e
      # ignore missing layout dir
    end

    def write
      Parallel.each(self.posts + self.pages + self.static_files) do |item|
        item.write(self.dest)
      end
    end

  end

end