Ruby csv 3.0.2

bench-parse.rb

require 'benchmark'
require 'csv'

TEST_FILE = 'test.csv'

unless File.exist?(TEST_FILE)
  ROW_SIZE = 1_000_000
  ROW = ('a'..'z').map { |c| %Q{"",""#{c}""\n""#{c}""\r""#{c}""\r\n""} }

  CSV.open(TEST_FILE, 'wb') do |csv|
    ROW_SIZE.times { csv << ROW }
  end
end

Benchmark.bm(16) do |x|
  x.report('CSV.foreach') do
    CSV.foreach(TEST_FILE) { |_| }
  end
end

__END__
ruby 2.5.3p105 (2018-10-18 revision 65156) [x86_64-linux]
                       user     system      total        real
CSV.foreach      185.305364   0.243049 185.548413 (185.557201)

ruby 2.6.0p0 (2018-12-25 revision 66547) [x86_64-linux]
                       user     system      total        real
CSV.foreach      149.647574   0.340243 149.987817 (150.005505)

bench-write.rb

require 'benchmark'
require 'csv'

N = 1_000_000
ROW = ('a'..'z').map { |c| %Q{"",""#{c}""\n""#{c}""\r""#{c}""\r\n""} }

Benchmark.bm(16) do |x|
  x.report('CSV.generate_line') do
    N.times do
      CSV.generate_line(ROW, encoding: 'UTF-8')
    end
  end

  x.report('CSV#string') do
    csv = CSV.new('')
    N.times do
      csv.reopen('')
      csv << ROW
      csv.string
    end
  end
end

__END__
ruby 2.5.3p105 (2018-10-18 revision 65156) [x86_64-linux]
                       user     system      total        real
CSV.generate_line104.335042   0.003767 104.338809 (104.323828)
CSV#string        70.865474   0.000000  70.865474 ( 70.862574)

ruby 2.6.0p0 (2018-12-25 revision 66547) [x86_64-linux]
                       user     system      total        real
CSV.generate_line 75.774594   0.004336  75.778930 ( 75.784888)
CSV#string        62.739028   0.000000  62.739028 ( 62.744933)