rspec_callsite_measurement.rb

#$null_stream = $stdout
$null_stream = File.open(File::NULL, 'w')

require 'rspec'
def start_runner
  RSpec::Core::Runner.run [], $null_stream, $null_stream
end

tp = TracePoint.new(:inline_cache_hit, :inline_cache_miss) do |x|
  p x.event
end

RSpec.send :describe, "foo" do
  N = (ENV['N'] || 100).to_i.times do |x|
    it "foo #{x.to_s}" do
      expect(true).to be
    end
  end
end

#start = Process.clock_gettime Process::CLOCK_MONOTONIC, :microsecond
tp.enable
start_runner
tp.disable
#p Process.clock_gettime(Process::CLOCK_MONOTONIC, :microsecond) - start