Profiling RubyWhere and what to optimize in your code

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jobs@housetrip.com /

Nasir Jamal work@HouseTrip

@_nasj

profiling helps you to narrow down towhere optimization would be most useful

benchmarking allows you to easily isolateoptimizations and cross-compare them

Benchmarking

Realtime

puts Benchmark.realtime { 4000.times { |x| x**x } }

#=> 0.905972957611084

1. User CPU time2. System CPU time3. (1 + 2) i.e. User + System CPU time4. Realtime

puts Benchmark.measure { 4000.times { |x| x**x } }

# => 0.890000 0.020000 0.910000 (0.909118)

Benchmark.bm do |bm| bm.report { first_algorithm } bm.report { second_algorithm} …..end

#=> user system total real 0.940000 0.010000 0.950000 ( 0.956572) 0.430000 0.010000 0.440000 ( 0.423467)

Benchmark.bm(14) do |bm| bm.report(“first header”) { first_algorithm } bm.report(“second header”) { second_algorithm} …..end

#=> user system total realfirst header 0.940000 0.010000 0.950000 (0.956572)second header 0.430000 0.010000 0.440000 (0.423467)

examples ...

Benchmark.bmbm(20) do |bm| bm.report('append') do str1, str2, str3, str4 = 'string1', 'string2', 'string3', 'string4' 1_000_000.times { y = str1 << str2 << str3 << str4 } end

bm.report('concat') do str1, str2, str3, str4 = 'string1', 'string2', 'string3', 'string4' 1_000_000.times { y = str1 + str2 + str3 + str4 } end

bm.report('interpolate') do str1, str2, str3, str4 = 'string1', 'string2', 'string3', 'string4' 1_000_000.times { y = "#{str1}#{str2}#{str3}#{str4}" } end

bm.report('interpolate one') do str1, str2, str3, str4 = 'string1', 'string2', 'string3', 'string4' 1_000_000.times { y = "string1string2string3#{str4}" } endend

.bmbm prevents result skewing

bmbm does rehearsal which includes any initialisation and GC runthen it does the real benchmark

#=> Rehearsal ---------------------------------------------append 0.280000 0.000000 0.280000 ( 0.294505)concat 0.470000 0.020000 0.490000 ( 0.481748)interpolate 0.430000 0.010000 0.440000 ( 0.433404)interpolate one 0.320000 0.000000 0.320000 ( 0.323479)--------------------------------------- total: 1.530000sec

| Tests | user | system | total | real ||:---------------|:--------:|:--------:|:---------:|-----------:||append | 0.260000 | 0.010000 | 0.270000 | (0.265732) ||concat | 0.400000 | 0.010000 | 0.410000 | (0.396115) ||interpolate | 0.400000 | 0.000000 | 0.400000 | (0.408096) ||interpolate one | 0.280000 | 0.010000 | 0.290000 | (0.286443) |

Benchmark.bmbm(20) do |bm| bm.report('gsub') do 1_0_000.times { Date.today.to_s.gsub!('-','') } end bm.report('strftime') do 1_0_000.times { Date.today.strftime("%Y%m%d") } endend

#=> Rehearsal -------------------------------------------gsub 0.750000 0.000000 0.750000 ( 0.751547)strftime 1.320000 0.000000 1.320000 ( 1.320621)------------------------------------ total: 2.070000sec

| | user | system | total | real ||:--------|:--------:|:---------:|:--------:|:-----------||gsub | 0.710000 | 0.000000 | 0.710000 | (0.709918) ||strftime | 1.320000 | 0.000000 | 1.320000 | (1.315345) |

module Extendable def name @name endend

class Person attr_accessor :nameend

require 'ostruct'Benchmark.bmbm(20) do |bm| bm.report('Class') do 1_00_000.times { p = Person.new; p.name='Joe'; p.name } end bm.report('Extends') do 1_00_000.times { p = Person1.new; p.extend Extendable; p.name='Joe'; p.name } end bm.report('Struct') do 1_00_000.times { person2 = Struct.new(:name); p = person2.new('Joe'); p.name } end bm.report('OpenStruct') do 1_00_000.times { p = OpenStruct.new(:name => 'Joe'); p.name } endend

#=> Rehearsal ---------------------------------------------Class 0.080000 0.000000 0.080000 (0.086261)Extends 0.410000 0.000000 0.410000 (0.407723)Struct 1.490000 0.000000 1.490000 (1.490557)OpenStruct 1.980000 0.010000 1.990000 (1.990507)------------------------------------ total: 3.970000sec

| | user | system | total | real ||:----------|:--------:|:--------:|:---------:|:-----------||Class | 0.080000 | 0.000000 | 0.080000 | (0.082448) ||Extends | 0.400000 | 0.000000 | 0.400000 | (0.410884) ||Struct | 1.480000 | 0.000000 | 1.480000 | (1.490531) ||OpenStruct | 1.960000 | 0.010000 | 1.970000 | (1.965923) |

Profiling

perftools.rban adaptation of Google's perftools library to the Ruby land by Aman

Guptahttps://github.com/tmm1/perftools.rb

$gem install perftools.rb

does profiling via sampling method, where by default it takes100 samples a second

examples ...

to see results

Interpreting the above columns:

1. Number of profiling samples in this function2. Percentage of profiling samples in this function3. Percentage of profiling samples in the functions printed so far4. Number of profiling samples in this function and its callees5. Percentage of profiling samples in this function and its callees6. Function name

a = ''PerfTools::CpuProfiler.start("/tmp/profiling/string_concat") do 100_000.times {|x| a += x.to_s}end

$pprof.rb --text --ignore=Gem /tmp/profiling/string_concatTotal: 2939 samples 1497 50.9% 50.9% 1501 51.1% Object#irb_binding 1438 48.9% 99.9% 1438 48.9% garbage_collector 4 0.1% 100.0% 1500 51.0% Integer#times

to see results as graph

bigger the box, the more time spent there

1. Class Name2. Method Name3. local (percentage)4. of cumulative (percentage)

brew install graphviz$pprof.rb --gif --ignore=Gem /tmp/profiling/string_concat > /tmp/profiling/string_concat.gif

slightly hairy method

And on on ....

PerfTools::CpuProfiler.start("/tmp/profiling/property_search") do 100.times { PropertySearch.new.search }end

$pprof.rb --text --ignore=Gem /tmp/profiling/property_search

Total: 6799 samples 2598 38.2% 38.2% 2598 38.2% garbage_collector 1761 25.9% 64.1% 3966 58.3% PropertySearch#set_price_filter_counts 390 5.7% 69.8% 1632 24.0% Object#detect 389 5.7% 75.6% 503 7.4% PropertySearch::PriceRange#contains? 358 5.3% 80.8% 358 5.3% Mysql2::Result#each 263 3.9% 84.7% 768 11.3% Object#select_values 199 2.9% 87.6% 236 3.5% ActiveRecord::ConnectionAdapters::Mysql2Adapter#execute 187 2.8% 90.4% 640 9.4% Property.collect_column 148 2.2% 92.6% 148 2.2% ActiveSupport::BufferedLogger#flush 114 1.7% 94.2% 114 1.7% Fixnum#<= 75 1.1% 95.3% 75 1.1% Array#join 67 1.0% 96.3% 76 1.1% Array#map 47 0.7% 97.0% 47 0.7% ActiveRecord::ConnectionAdapters::Column#type_cast 44 0.6% 97.7% 295 4.3% Array#collect 32 0.5% 98.1% 388 5.7% Object#to_a 28 0.4% 98.5% 28 0.4% PropertySearch#day_count 15 0.2% 98.8% 140 2.1% ActiveRecord::ConnectionAdapters::Mysql2Adapter#select 9 0.1% 98.9% 4199 61.8% PropertySearch#search

$pprof.rb --help

QcachegrindHow to setup?

http://langui.sh/2011/06/16/how-to-install-qcachegrind-

kcachegrind-on-mac-osx-snow-leopard/

$pprof.rb --callgrind /tmp/profiling/property_search > /tmp/profiling/property_search.callgrind

graph

To use with Rails

Valid default_printer values are pdf, text, raw, gif, callgrind

# Gemfilegem 'rack-perftools_profiler', :require => false

# config/environment.rbconfig.middleware.use ::Rack::PerftoolsProfiler, :default_printer => 'gif', :bundler => true, :mode => :cputime, :frequency => 250

profile=true will enable profilingtimes=10 will hit the page for 10 timeswill store the results in profile_ppp_page.txt

RACK_PROFILER=true script/server

curl -o profile_ppp_page.txt \"http://localhost:3000/en/rentals/107605?profile=true&times=10"

ruby-prof

OR

$gem install ruby-prof

#Gemfile gem 'ruby-prof', :require => false

types of measuresRubyProf.measure_mode = RubyProf::PROCESS_TIMERubyProf.measure_mode = RubyProf::WALL_TIMERubyProf.measure_mode = RubyProf::CPU_TIMERubyProf.measure_mode = RubyProf::ALLOCATIONSRubyProf.measure_mode = RubyProf::MEMORYRubyProf.measure_mode = RubyProf::GC_RUNSRubyProf.measure_mode = RubyProf::GC_TIME

types of printersRubyProf::FlatPrinterRubyProf::FlatPrinterWithLineNumbersRubyProf::GraphPrinterRubyProf::GraphHtmlPrinterRubyProf::CallTreePrinterRubyProf::CallStackPrinterRubyProf::MultiPrinter

examples ...

GraphHtmlPrinterresult = RubyProf.profile { PropertySearch.new.search }

printer = RubyProf::GraphHtmlPrinter.new(result)

File.open("tmp/profile_data.html", 'w') { |file| printer.print(file)}

profile_data.html

CallStackPrinterresult = RubyProf.profile { PropertySearch.new.search }

printer = RubyProf::CallStackPrinter.new(result)

File.open("tmp/profile_data.html", 'w') { |file| printer.print(file)}

profile_data.html

CallTreePrinterresult = RubyProf.profile { PropertySearch.new.search }

printer = RubyProf::CallTreePrinter.new(result)

File.open("tmp/profile_data", 'w') { |file| printer.print(file)}

profile_data (qcachegrind)

In Rails2.x.x

3.x.x

Or just use rake tasks

script/performance/benchmarker 10 'Class.method_name' 'AnotherClass.method_name'

script/performance/profiler 'Class.method_name' 10 graph

script/performance/profiler 'Class.method_name' 10 graph_html 2> property.html && open property.html

rails benchmarker 'Class.method_name'

rails profiler 'Class.method_name' --runs 3 --metrics cpu_time,memory

rake test:benchmarkrake test:profile

rake test:profile TEST=test/performance/home_page_test.rb

But from Rails 4.0performance tests are no longer part of the default

stackhttps://github.com/rails/rails-perftest

Questions?

jobs@housetrip.comWe are hiring

Thank you