gem install rblineprof
Or in your Gemfile:
gem 'rblineprof'
require 'rblineprof'
profile = lineprof(/./) do
  sleep 0.001
  100.times do
    sleep 0.001
    1*2*3
    4*5*6
    7*8*9*10*11*12*13*14*15
    2**32
    2**128
  end
end
file = profile.keys.first
File.readlines(file).each_with_index do |line, num|
  wall, cpu, calls, allocations = profile[file][num + 1]
  if wall > 0 || cpu > 0 || calls > 0
    printf(
      "% 5.1fms + % 6.1fms (% 4d) | %s",
      cpu / 1000.0,
      (wall - cpu) / 1000.0,
      calls,
      line
    )
  else
    printf "                          | %s", line
  end
end
Will give you:
                          | require 'rblineprof'
                          | 
                          | profile = lineprof(/./) do
  0.1ms +    1.4ms (   1) |   sleep 0.001
                          | 
  2.7ms +  132.2ms (   1) |   100.times do
  1.3ms +  131.7ms ( 100) |     sleep 0.001
                          | 
                          |     1*2*3
                          |     4*5*6
                          |     7*8*9*10*11*12*13*14*15
  0.1ms +    0.1ms ( 100) |     2**32
  0.6ms +    0.1ms ( 100) |     2**128
                          |   end
                          | end
                          | 
                          | file = profile.keys.first
                          | 
                          | File.readlines(file).each_with_index do |line, num|
                          |   wall, cpu, calls, allocations = profile[file][num + 1]
                          | 
                          |   if wall > 0 || cpu > 0 || calls > 0
                          |     printf(
                          |       "% 5.1fms + % 6.1fms (% 4d) | %s",
                          |       cpu / 1000.0,
                          |       (wall - cpu) / 1000.0,
                          |       calls,
                          |       line
                          |     )
                          |   else
                          |     printf "                          | %s", line
                          |   end
                          | end
- PLine line-profiler for ruby 1.9
 - pure-ruby LineProfiler for ruby 1.6
 - method_profiler
 - ruby-prof
 - perftools.rb
 - zenprofile
 
rblineprof is released under the MIT License.