vimbench.rb

require 'pathname'
require 'fileutils'

LOG_PATH = Pathname('/tmp/vimbench.log')
RE = /(\d+\.\d+)\s*\d+\.\d+:\s*--- N?VIM STARTED ---/
N = 10


def prepare
  FileUtils.rm LOG_PATH if LOG_PATH.exist?
  FileUtils.touch LOG_PATH

  q = Queue.new

  th = Thread.new do
    IO.popen('tail -f /tmp/vimbench.log') do |io|
      io.each_line do |line|
        q << Object.new if line =~ RE
      end
    end
  end

  return q, th
end

def clear(q, th)
  q.close
  th.kill
end

def stats
  content = LOG_PATH.read
  content.scan(RE).flatten.map(&:to_f)
end

def format(stats)
  <<~END
    results: #{stats.join ' '}
    average: #{stats.sum / stats.size}
  END
end

q, th = prepare

N.times do
  pid = spawn("vim --startuptime #{LOG_PATH}")
  q.pop
  Process.kill :SIGTERM, pid
end

clear q, th

vimrc_stat = stats

q, th = prepare

# default
N.times do
  pid = spawn("vim -u DEFAULTS --startuptime #{LOG_PATH}")
  q.pop
  Process.kill :SIGTERM, pid
end

clear q, th

no_vimrc_stat = stats

system 'reset'

puts <<~END


  with vimrc
  #{format vimrc_stat}

  no vimrc
  #{format no_vimrc_stat}

  #{sprintf("%.3f", vimrc_stat.sum / no_vimrc_stat.sum)}x slower your Vim than the default.
END

FileUtils.rm LOG_PATH

with vimrc
results: 253.252 253.791 245.451 252.825 253.659 243.336 242.436 248.03 243.538 276.004
average: 251.2322


no vimrc
results: 14.158 8.689 21.326 12.332 10.666 13.07 13.095 11.285 9.083 14.953
average: 12.8657


19.527x slower your Vim than the default.