[ruby-core:90298] [Ruby trunk Feature#15380] faster method lookup for Array#all? #none? #one?

[shevegen@gmail.com]

Issue #15380 has been updated by shevegen (Robert A. Heiler).


While I agree with Koichi in regards to benchmarks and more code 
meaning more maintenance work (naturally), I think it should still
be considered for the trade off being potentially worth it. If there
is time for discussion at the next developer meeting perhaps matz
could be asked.

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Feature #15380: faster method lookup for Array#all? #none?  #one?
https://bugs.ruby-lang.org/issues/15380#change-75405

* Author: fursich (Onishi Koji)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
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## summary

This PR proposes Array-specific implementations for `#all?` , `#none?` and `#one?` to enable faster method lookup.

Before this patch `Array#all?` was not implemented in Array class, so alternatively, `Enumerable#all?` was used each time the method is called.

On the other hand, `#any?` has its own method entry in Array class for faster method calls.

This patch provides above three methods with Array-specific implementations that are equivalent to what `Array#any?` has.


https://github.com/ruby/ruby/pull/2041



## benchmark


~~~ text
**********************************************************************************
benchmarking Array#all?
**********************************************************************************

Calculating -------------------------------------
    Array#all? (new)          421.298 i/s -      1.000k times in 2.373616s (2.37ms/i)
    Array#all? (old)          335.364 i/s -      1.000k times in 2.981838s (2.98ms/i)

Comparison:
    Array#all? (new):       421.3 i/s
    Array#all? (old):       335.4 i/s - 1.26x  slower

<running with --jit>
Calculating -------------------------------------
    Array#all? (new)                244.929 i/s -      1.000k times in 4.082823s (4.08ms/i)
    Array#all? (old)                210.354 i/s -      1.000k times in 4.753895s (4.75ms/i)

Comparison:
    Array#all? (new):       244.9 i/s
    Array#all? (old):       210.4 i/s - 1.16x  slower
~~~

Attached benchmark shows the full benchmark results:

https://gist.github.com/fursich/1d1bad353ddc2f4b510b34e3191fd302


Each method gets approx. 10-20% faster with repeated calls.
It only impacts on method lookup (not execution itself), but at least it should make` Array#all?` work as just efficiently as `Array#any?` does.


## estimate of impact

Just to provide a rough picture on how frequently these methods are used in real world app, here shows a quick-and-dirty investigations I did with [rails](https://github.com/rails/rails) (using its latest master as of Dec 5):

~~~ text
rails (master)$ git grep '\.all?' | wc -l
      80
rails (master)$ git grep '\.one?' | wc -l
      13
rails (master)$ git grep '\.none?' | wc -l
      25
~~~

while
~~~ text
rails (master)$ git grep '\.any?' | wc -l
~~~

(* the result includes non-Array method. the intention here is just to give rough estimate on how frequently these methods are used compared with each other)

It's probably fair to say the use of the three methods (118 lines in total here) are *not* ignorably rare compared to `#all?`


## motivation behind it

In developing Ruby apps we encounter (often non essential) discussion around 'which method call is faster?', 'should we use this method for efficiency?'.

As Ruby lover I really hope to pick methods based on pure readability and Ruby-ness, 

Hopefully it helps Ruby become faster even at slightest level :)




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