emerose-perftools.rb

google-perftools for ruby code (c) 2009 Aman Gupta (tmm1)

=== Usage

Run the profiler with a block:

require 'perftools'
PerfTools::CpuProfiler.start("/tmp/add_numbers_profile") do
  5_000_000.times{ 1+2+3+4+5 }
end

Start and stop the profiler manually:

require 'perftools'
PerfTools::CpuProfiler.start("/tmp/add_numbers_profile")
5_000_000.times{ 1+2+3+4+5 }
PerfTools::CpuProfiler.stop

Profile an existing ruby application without modifying it:

$ CPUPROFILE=/tmp/my_app_profile RUBYOPT="-r`gem which perftools | tail -1`" ruby my_app.rb

=== Reporting

pprof.rb --text /tmp/add_numbers_profile

pprof.rb --pdf /tmp/add_numbers_profile > /tmp/add_numbers_profile.pdf

pprof.rb --gif /tmp/add_numbers_profile > /tmp/add_numbers_profile.gif

pprof.rb --callgrind /tmp/add_numbers_profile > /tmp/add_numbers_profile.grind kcachegrind /tmp/add_numbers_profile.grind

pprof.rb --gif --focus=Integer /tmp/add_numbers_profile > /tmp/add_numbers_custom.gif

pprof.rb --text --ignore=Gem /tmp/my_app_profile

For more options, see http://google-perftools.googlecode.com/svn/trunk/doc/cpuprofile.html#pprof

=== Examples

pprof.rb --text

Total: 1735 samples
    1487  85.7%  85.7%     1735 100.0% Integer#times
     248  14.3% 100.0%      248  14.3% Fixnum#+

pprof.rb --gif

Simple require 'rubygems' profile

  http://perftools-rb.rubyforge.org/examples/rubygems.gif

Comparing redis-rb with and without SystemTimer based socket timeouts

  http://perftools-rb.rubyforge.org/examples/redis-rb.gif
  http://perftools-rb.rubyforge.org/examples/redis-rb-notimeout.gif

Sinatra vs. Merb vs. Rails

  http://perftools-rb.rubyforge.org/examples/sinatra.gif
  http://perftools-rb.rubyforge.org/examples/merb.gif
  http://perftools-rb.rubyforge.org/examples/rails.gif

C-level profile of EventMachine + epoll + Ruby threads
  before http://timetobleed.com/6-line-eventmachine-bugfix-2x-faster-gc-1300-requestssec/

  http://perftools-rb.rubyforge.org/examples/eventmachine-epoll+nothreads.gif
  http://perftools-rb.rubyforge.org/examples/eventmachine-epoll+threads.gif

C-level profile of the ruby interpreter
  12% time spent in re_match_exec because of excessive calls to rb_str_sub_bang by Date.parse
  easily fixed by using the ThirdBase gem

  http://perftools-rb.rubyforge.org/examples/ruby_interpreter.gif

=== Installation

Just install the gem, which will download, patch and compile google-perftools for you:

sudo gem install perftools.rb

Or use the dev gem from github:

gem install -s http://gems.github.com tmm1-perftools.rb

Or build your own gem:

git clone git://github.com/tmm1/perftools.rb
cd perftools.rb
gem build perftools.rb.gemspec
gem install perftools.rb

You'll also need graphviz to generate call graphs using dot:

sudo port install graphviz     # osx
sudo apt-get install graphviz  # debian/ubuntu

=== Advantages over ruby-prof

Sampling profiler

perftools samples your process using setitimer() so it can be used in production with minimal overhead.

=== Profiling the Ruby VM and C extensions

To profile C code, download and build an unpatched perftools (libunwind or ./configure --enable-frame-pointers required on x86_64):

wget http://google-perftools.googlecode.com/files/google-perftools-1.2.tar.gz
tar zxvf google-perftools-1.2.tar.gz
cd google-perftools-1.2

./configure --prefix=/opt --disable-shared
make
sudo make install

export LD_PRELOAD=/opt/lib/libprofiler.so                 # for linux
export DYLD_INSERT_LIBRARIES=/opt/lib/libprofiler.dylib   # for osx
CPUPROFILE=/tmp/ruby_interpreter.profile ruby -e' 5_000_000.times{ "hello world" } '

pprof `which ruby` --text /tmp/ruby_interpreter.profile

=== TODO

• Add support for heap profiling to find memory leaks (PerfTools::HeapProfiler)
• Allow both C and Ruby profiling
• Add setter for the sampling interval
• Add support for ruby 1.9

=== Resources

GoRuCo 2009 Lightning Talk on perftools.rb http://goruco2009.confreaks.com/30-may-2009-18-35-rejectconf-various-presenters.html at 21:52

Ilya Grigorik's introduction to perftools.rb http://www.igvita.com/2009/06/13/profiling-ruby-with-googles-perftools/

Google Perftools http://code.google.com/p/google-perftools/

Analyzing profiles and interpreting different output formats http://google-perftools.googlecode.com/svn/trunk/doc/cpuprofile.html#pprof