Bug #14695: [2.5.1] `===` is 1.77x slower than `match?`

• Status: Closed
• Assignee: -
• Target version: -
• ruby -v: ruby 2.5.1p57 (2018-03-29 revision 63029) [x86_64-darwin17]
• Backport: 2.3: UNKNOWN, 2.4: UNKNOWN, 2.5: UNKNOWN

[baweaver (Brandon Weaver)]

Was evaluating some of the === implementations while testing and came across this one:

# ruby 2.5.1p57 (2018-03-29 revision 63029) [x86_64-darwin17]

require 'benchmark/ips'

def run_benchmark(title, **benchmarks)
  puts '', title, '=' * title.size, ''

  # Validation
  benchmarks.each do |benchmark_name, benchmark_fn|
    puts "#{benchmark_name} result: #{benchmark_fn.call()}"
  end

  puts

  Benchmark.ips do |bm|
    benchmarks.each do |benchmark_name, benchmark_fn|
      bm.report(benchmark_name, &benchmark_fn)
    end

    bm.compare!
  end
end

regex = /foo/
# => /foo/
string = 'foobarbaz'
# => "foobarbaz"

run_benchmark('=== vs match? - 2.5.1',
  '===':    -> { regex === string },
  'match?': -> { regex.match? string }
)

=== vs match? - 2.5.1
=====================

=== result: true
match? result: true

Warming up --------------------------------------
                 ===   173.435k i/100ms
              match?   233.124k i/100ms
Calculating -------------------------------------
                 ===      3.174M (± 1.6%) i/s -     15.956M in   5.029027s
              match?      5.626M (± 2.5%) i/s -     28.208M in   5.016991s

Comparison:
              match?:  5626170.1 i/s
                 ===:  3173659.6 i/s - 1.77x  slower

It appears that === is running a bit slower than match?, though there may be some concerns around old code potentially relying on regex set globals after === too in case statements, so not sure there.

[shyouhei (Shyouhei Urabe)]

baweaver (Brandon Weaver) wrote:

It appears that === is running a bit slower than match?

Accurate observation. Regexp#match? was introduced as a "faster alternative" to ordinary matches; see also https://bugs.ruby-lang.org/issues/8110

[shyouhei (Shyouhei Urabe)]

• Related to Feature #8110: Regex methods not changing global variables added

[jeremyevans0 (Jeremy Evans)]

• Status changed from Open to Closed