gistfile1.txt

require 'benchmark/ips'

env = {"foo" => "bar", "bar" => "baz", "baz" => "boo", "PATH_INFO" => "foo"}

Benchmark.ips do |x|
  x.report("set and reset") do
    env["PATH_INFO"] = "zoo"
    env
    env["PATH_INFO"] = "foo"
  end
  x.report("merge") { env.merge("PATH_INFO" => "zoo") }
  x.report("dup") { env.dup["PATH_INFO"] = "zoo"}
end