From: pdahorek@...
Date: 2017-08-27T16:22:12+00:00
Subject: [ruby-core:82482] [Ruby trunk Bug#13167] Dir.glob is 25x slower	since Ruby 2.2

Issue #13167 has been updated by ahorek (Pavel Rosick��).


Ok, one minnor improvement, I think there's an unnecessary fd call for "." in recursion mode

https://github.com/ruby/ruby/pull/1685

I reverted nobu's change and instead of recursion for simple patterns I want to call "replace_real_basename" only for results. There's no need to call it for each directory because the result will always be same. It's not final and I'll be really glad if someone more experienced can help me with it.
Also other parts like path normalization could be called only once.

What do you think about optimizing most common use cases like
**Dir.glob('/test/file.{html,erb}')**
**Dir.glob('/test/*')**
?

Ruby 2.4.1

~~~
               plain:     1089.3 i/s
                   *:      324.9 i/s
              braces:       37.7 i/s
                 * 2:        8.6 i/s
                  **:        3.1 i/s
~~~

Trunk (2.5)

~~~
               plain:     1013.7 i/s
                   *:      569.6 i/s
              braces:       34.7 i/s
                 * 2:       23.3 i/s
                  **:        2.8 i/s
~~~

Trunk (2.5) + patch

~~~
               plain:    18020.3 i/s
                   *:     1432.5 i/s
              braces:      917.7 i/s
                 * 2:       25.4 i/s
                  **:        3.1 i/s
~~~
                  
Ruby 2.1.9

~~~
               plain:    20519.1 i/s
                   *:     1905.2 i/s
              braces:     1094.0 i/s
                 * 2:       46.4 i/s
                  **:        6.7 i/s
~~~
btw Python's performace is even faster then Ruby 2.1.9 (20x), this is a huge difference.

----------------------------------------
Bug #13167: Dir.glob is 25x slower since Ruby 2.2
https://bugs.ruby-lang.org/issues/13167#change-66293

* Author: ahorek (Pavel Rosick��)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
* ruby -v: 2.4.0
* Backport: 2.2: UNKNOWN, 2.3: UNKNOWN, 2.4: UNKNOWN
----------------------------------------
Hello,
we've found a huge speed regression in our Rails app. After some digging the reason is in `Dir.glob` method which is much slower since Ruby 2.2.6. This is probably Windows only!

This code is used heavily in Rails for partial lookups:

```ruby
Dir.glob('c:/test/myapp/app/views/common/_menu_stats{.en,}{.html,}{}{.erb,.builder,.raw,.ruby,.jbuilder,.coffee,}')
```

Comparsion (x64):
jruby 9.1.7.0 2540 i/s
ruby 2.1.5 2568 i/s
ruby 2.1.9 2569 i/s
**ruby 2.2.6 99 i/s 25 times slower!
ruby 2.3.3 102 i/s
ruby 2.4.0 103 i/s**

I would like to help, but I don't know much about Ruby C internals. Please let me know if you need any additional info. Now we're stuck at 2.1.9 because this issue makes the development on more recent versions unusable.

---Files--------------------------------
logruby24.txt (484 KB)
logruby21.txt (10.8 KB)


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