Stupid Analysis of `strace` Output

strace_parser.rb

#!/usr/bin/env ruby
#
# Usage:
# strace_parser.rb < file.out
# head -n100 file.out | strace_parser.rb
# strace_parser.rb file.out

class StraceEntry
  attr_accessor :line
  attr_accessor :pid, :timestamp, :command, :args, :result, :runtime

  # Assumes `strace -tt -T`
  MATCHER = %r[(\d+)\s+(\d{2}:\d{2}:\d{2}.\d{6}) (\w+)\((.*)\) = (\d+) <(.*)>]

  def initialize(line)
    self.line = line
    parse_line
  end

  private

  def parse_line
    line.match(MATCHER) do |match|
      self.pid = match[1].to_i
      self.timestamp = match[2]
      self.command = match[3]
      self.args = match[4]
      self.result = match[5]
      self.runtime = match[6].to_f
    end
  end
end

entries = []

ARGF.each_line do |line|
  if line =~ StraceEntry::MATCHER
    entries << StraceEntry.new(line)
  end
end

puts "Matched #{entries.count} entries"

groups = entries.group_by(&:command)

puts "Grouped into #{groups.keys.count} commands"

groups.each do |command, es|
  puts "#{command}: #{es.map(&:runtime).inject(:+)}"
end