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Diffstat (limited to 'lib/gitlab/sherlock/line_profiler.rb')
-rw-r--r-- | lib/gitlab/sherlock/line_profiler.rb | 98 |
1 files changed, 98 insertions, 0 deletions
diff --git a/lib/gitlab/sherlock/line_profiler.rb b/lib/gitlab/sherlock/line_profiler.rb new file mode 100644 index 00000000000..aa1468bff6b --- /dev/null +++ b/lib/gitlab/sherlock/line_profiler.rb @@ -0,0 +1,98 @@ +module Gitlab + module Sherlock + # Class for profiling code on a per line basis. + # + # The LineProfiler class can be used to profile code on per line basis + # without littering your code with Ruby implementation specific profiling + # methods. + # + # This profiler only includes samples taking longer than a given threshold + # and those that occur in the actual application (e.g. files from Gems are + # ignored). + class LineProfiler + # The minimum amount of time that has to be spent in a file for it to be + # included in a list of samples. + MINIMUM_DURATION = 10.0 + + # Profiles the given block. + # + # Example: + # + # profiler = LineProfiler.new + # + # retval, samples = profiler.profile do + # "cats are amazing" + # end + # + # retval # => "cats are amazing" + # samples # => [#<Gitlab::Sherlock::FileSample ...>, ...] + # + # Returns an Array containing the block's return value and an Array of + # FileSample objects. + def profile(&block) + if mri? + profile_mri(&block) + else + raise NotImplementedError, + 'Line profiling is not supported on this platform' + end + end + + # Profiles the given block using rblineprof (MRI only). + def profile_mri + require 'rblineprof' + + retval = nil + samples = lineprof(/^#{Rails.root.to_s}/) { retval = yield } + + file_samples = aggregate_rblineprof(samples) + + [retval, file_samples] + end + + # Returns an Array of file samples based on the output of rblineprof. + # + # lineprof_stats - A Hash containing rblineprof statistics on a per file + # basis. + # + # Returns an Array of FileSample objects. + def aggregate_rblineprof(lineprof_stats) + samples = [] + + lineprof_stats.each do |(file, stats)| + source_lines = File.read(file).each_line.to_a + line_samples = [] + + total_duration = microsec_to_millisec(stats[0][0]) + total_events = stats[0][2] + + next if total_duration <= MINIMUM_DURATION + + stats[1..-1].each_with_index do |data, index| + next unless source_lines[index] + + duration = microsec_to_millisec(data[0]) + events = data[2] + + line_samples << LineSample.new(duration, events) + end + + samples << FileSample. + new(file, line_samples, total_duration, total_events) + end + + samples + end + + private + + def microsec_to_millisec(microsec) + microsec / 1000.0 + end + + def mri? + RUBY_ENGINE == 'ruby' + end + end + end +end |