Benchmark RubyGem load times
Maybe you are curious like me and you would like to check how long your gems take to load, or maybe you have a considerable codebase which uses many gems and you are concerned with the time it takes to load all of them.
At HouseTrip we have a rake task that allow us to benchmark the loading times of each gem on the web application, which I would like to share with you.
The solution is fairly simple and makes use of the ruby builtin Benchmark module which allow us to see how long does it take to load each individual gem.
# lib/tasks/benchmarks.rake
namespace "benchmarks" do
desc "shows gem load times"
task :gem_load_times do
require 'rubygems'
require 'bundler'
require 'benchmark'
require 'pry'
ORIGINAL_ENV = ENV.clone
$stderr = StringIO.new
reports = Benchmark.bmbm() do |x|
x.report("Bundler.setup") { Bundler.setup }
Bundler.setup.gems.each do |gem|
ENV.replace(ORIGINAL_ENV)
Gem.source_index.instance_variable_set(:@gems, {})
x.report("#{gem.name} (#{gem.version})") do
begin
require gem.name.underscore
rescue LoadError
print "*"
rescue
print "**"
end
end
end
end
puts "*: there was an error loading the gem"
puts "**: there was an error after loading the gem"
end
end
