focal_point¶ ↑

An unobtrusive profiling utility, for ruby, based on hitimes.

• hitimes provides excellent timers (low overhead, high resolution)

• focal_point helps you use them, without polluting the code you’re interested in.

1. Tell FocalPoint to watch one or more methods

2. Execute the methods you’re interested in

3. Ask FocalPoint for a report

4. Enjoy

Given a contrived implementation:

class Foo
  def self.bar
    rand(10).times { sleep(1) }
  end
  def bin
    Foo.bar
  end
end

You’re wondering how much time you spend executing Foo.bar and Foo#bin.

# 1. Tell FocalPoint to watch one or more methods
require 'foo'
require 'focal_point'
FocalPoint.watch('Foo.bar') # eg: class method
FocalPoint.watch('Foo#bin') # eg: instance method

# 2. Execute the methods you're interested in
rand(10).times { Foo.bar }
rand(10).times { Foo.new.bin }

# 3. Ask FocalPoint to report what happened
FocalPoint.report  ## report accepts an IO object, if you want to send it somewhere else.

# 4. Enjoy.
#
# You should see something like this in your stdout.
#
# --------------------------------------------------------------------------------
# sum: 7.003960149
# name: Foo.bar
# sampling_stop_time: 1.26255541894458e+15
# sumsq: 25.03019390208
# sampling_start_time: 1.26255541194084e+15
# rate: 0.285552738372669
# max: 4.003211068
# mean: 3.5019800745
# count: 2
# stddev: 0.708847668889441
# min: 3.000749081
#
# --------------------------------------------------------------------------------
# sum: 25.003881843
# name: Foo#bin
# sampling_stop_time: 1.26255621470907e+15
# sumsq: 151.046337138512
# sampling_start_time: 1.26255618970493e+15
# rate: 0.199968950077237
# max: 7.001084262
# mean: 5.0007763686
# count: 5
# stddev: 2.54987821742389
# min: 1.000180239
# additional_data:

This, or variations of it were happening way to often:

Foo.class_eval do
  def self.bar_timer
    @bar_timer ||= Hitimes::TimedMetric.new("Foo#bar")
  end
  alias_method :real_bar, :bar
  def bar *args
    self.class.bar_timer.start
    result = real_bar(*args)
    self.class.bar_timer.stop
    result
  end
end

• Fork the project.

• Make your feature addition or bug fix.

• Add tests for it. This is important so I don’t break it in a future version unintentionally.

• Commit, do not mess with rakefile, version, or history. (if you want to have your own version, that is fine but bump version in a commit by itself I can ignore when I pull)

• Send me a pull request. Bonus points for topic branches.

Copyright © 2010 levicook@gmail.com. See LICENSE for details.