Excessive use of CPU

Hello guys and girls, I have a problem with a method (new), it is
using 100% of CPU for 15/20 seconds. Follow the method below:

http://pastie.org/537568

## kits_controller.rb
def new
  @page_title = 'Add a Kit'
  @kit = Kit.new

  @num_itens = 16
  @kit_inclusions = Array.new
  @num_itens.times { @kit_inclusions.push(KitInclusion.new) }

    render :action => 'form'
end

def new_do
  kit = Kit.new(params[:form])

  if kit.save
    params[:kit_inclusions].each do |ki|
      next if ki[:product_id].empty?

      kit_inclusion = KitInclusion.new(ki)
      kit_inclusion.kit_id = kit.id
      kit_inclusion.save
    end

    flash[:notice] = 'Kit added!'
    redirect_to :action => 'index'
  else
    flash[:notice] = kit.errors.full_messages.map {|fm| "<li>#{fm}</

"}

    redirect_to :action => 'new'
  end
end

## form.hmtl.erb
<% form_for :form, @kit, :url => { :action => action_do } do |f| -%>
    <% @num_itens.times do |t| -%>
  <% fields_for "kit_inclusions[]", @kit_inclusions[t] do |i| -%>
      <li><label><strong>Product <%= t + 1 %>:</strong></label><%=
i.collection_select "product_id", Product.all(:conditions =>
{:available => true}, :order => "category_id, model
ASC"), :id, :display_for_select, {:include_blank => 'Select...'},
{:onchange => "qntDefault(\'quantity_#{t}\');"} %><%= i.text_field
"quantity", {:onkeydown => "return noLetters(event);", :class =>
'quantity', :id => "quantity_#{t}"} %></li>
        <% end -%>
    <% end -%>
    <%= image_submit_tag 'btn_save.png' %></div>
    <%= f.hidden_field :id %>
<% end -%>

Can you give more information on your environment? It shouldn't be
taking that long...

I'd also advise you to read more documentation; some parts of your
code are working against the Rails default conventions (for instance:
the action that creates records is typically 'create', not 'new_do').
It's a small thing, but it means that you have to do extra typing
(example: the :url option to form_for).

You may also, if you're on 2.3, want to look into the nested model
support stuff, which will handle much of what you're doing here.

--Matt Jones

Hello Matt, thanks for the atention.

I'm under Ruby 1.8.6 and Rails 2.3.2. The machine is a Macbook Pro
with a Core 2 Duo 2.4GHz and 4GB of RAM. I have declared the nested
conditions in the model as seen bellow.

class Kit < ActiveRecord::Base

  has_many :kit_inclusions
  has_many :products, :through => :kit_inclusions

  accepts_nested_attributes_for :kit_inclusions, :allow_destroy =>
true

  def before_validation
    self.name = self.name.to_s.strip.downcase.titleize
    self.comments = self.comments.to_s.strip.capitalize
  end

  validates_presence_of :name, :message => 'é requerido'

  def to_s
    self.name
  end

end