From: Eric Wong <e@yhbt.net> To: Jean Boussier <jean.boussier@shopify.com> Cc: unicorn-public@yhbt.net Subject: Re: [PATCH] Add early hints support Date: Mon, 20 Jul 2020 10:55:38 +0000 [thread overview] Message-ID: <20200720105538.GA13340@dcvr> (raw) In-Reply-To: <F908D215-8646-450C-BA7F-9704F1E9D738@shopify.com> Jean Boussier <jean.boussier@shopify.com> wrote: > > `match?' is Ruby 2.4+, which is probably too big a jump since > > we're still on Ruby 1.9.3 at the moment... > > That's what I figured. > > > String comparison as in `==' and `!='? Would be interested to know > > where and what improvements can be had. Thanks for the benchmarks. > One place that jumped to mind when I saw it is http_response_write. > But there are many other places where Regexp are used to do case > insensitive comparisons. > > ``` > require 'benchmark/ips' > > def http_response_write(headers) > headers.each do |key, value| > case key > when %r{\A(?:Date|Connection)\z}i > next > end > end > end > > def http_response_write_upcase(headers) > headers.each do |key, value| > case key.upcase > when 'DATE'.freeze, 'CONNECTION'.freeze > next > end > end > end > > def http_response_write_casecmp(headers) > headers.each do |key, value| > case key > when key.casecmp?('Date'.freeze) || key.casecmp?('Connection'.freeze) > next > end > end > end > > HEADERS = { > 'Foo' => 'bar', > 'Date' => 'plop', > 'User-Agent' => 'blah', > } > > Benchmark.ips do |x| > x.report('original') { http_response_write(HEADERS) } > x.report('upcase') { http_response_write_upcase(HEADERS) } > x.report('casecmp?') { http_response_write_casecmp(HEADERS) } > x.compare! > end > ``` > > ``` > Warming up -------------------------------------- > original 82.066k i/100ms > upcase 177.429k i/100ms > casecmp? 96.288k i/100ms > Calculating ------------------------------------- > original 831.610k (± 1.6%) i/s - 4.185M in 5.034146s > upcase 1.770M (± 1.6%) i/s - 8.871M in 5.013796s > casecmp? 979.618k (± 1.3%) i/s - 4.911M in 5.013678s > > Comparison: > upcase: 1769883.2 i/s > casecmp?: 979618.3 i/s - 1.81x (± 0.00) slower > original: 831610.2 i/s - 2.13x (± 0.00) slower > ``` upcase seems VERY compelling in a micro benchmark since it can go straight into opt_case_dispatch. But I worry the extra garbage might have a different effect in a real app, especially with more headers. > Similarly, that method use `value =~ /\n/` which could be replaced > favorably for `value.include?("\n".freeze)` Yes, we tried that a few years ago and broke existing code that had `nil' value, so it was promptly reverted: https://yhbt.net/unicorn-public/CAO47=rJa=zRcLn_Xm4v2cHPr6c0UswaFC_omYFEH+baSxHOWKQ@mail.gmail.com/ Maybe: (val || ''.freeze).include?("\n".freeze) Can work for those buggy apps, though... > ``` > VAL = "foobar" > Benchmark.ips do |x| > x.report('=~') { VAL =~ /\n/ } > x.report('include?') { VAL.include?("\n".freeze) } > x.compare! > end > > Ruby just seems hopeless performance-wise > > Well, the gap between 1.9.3 and 2.5+ is pretty big performance-wise. True, but it's still pretty slow :>
next prev parent reply other threads:[~2020-07-20 10:55 UTC|newest] Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-07-16 10:05 Jean Boussier 2020-07-16 10:50 ` Eric Wong 2020-07-16 11:41 ` Jean Boussier 2020-07-16 12:16 ` Eric Wong 2020-07-16 12:24 ` Jean Boussier 2020-07-17 1:19 ` Eric Wong 2020-07-20 9:18 ` Jean Boussier 2020-07-20 10:09 ` Eric Wong 2020-07-20 10:27 ` Jean Boussier 2020-07-20 10:55 ` Eric Wong [this message] 2020-07-20 11:53 ` Jean Boussier 2020-07-20 20:27 ` Eric Wong
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