[ruby-core:113686] [Ruby master Misc#19693] Data initialization is significantly slower than Struct

27 May 2023

      Issue #19693 has been updated by janosch-x (Janosch Müller).
...
I suppose it wouldn't hurt.
I think its beautiful 😁

Another option could be to bypass the initializer by default and only patch it into a Data subclass when `initialize` is redefined (as detected via `method_added` or so).
...
Defining a `new` singleton method on the Data subclass, in Ruby and with explicit keyword arguments should be able to then use the literal kwargs optimization
@Eregon Wouldn't that require exposing some kind of alternate, non-freezing initializer to Ruby, or some setter methods? This seems to go a bit against the immutable spirit of the class. Also, wouldn't defining `new` in Ruby slow down initialization with positional/list arguments? Maybe the solution would rather be to auto-define a `keyword_initialize` method or so in Ruby and let `new`, still in C, delegate to that method when given kwargs?

BTW using literal kwargs in Ruby also makes struct initialization with keywords 3 times faster:

```ruby
require 'benchmark/ips'

S1 = Struct.new(:a, :b, :c, :d, :e, :f, :g, :h, :i, :j)
S2 = Struct.new(:a, :b, :c, :d, :e, :f, :g, :h, :i, :j)

class << S2
  alias orig_new new
  def new(a: nil, b: nil, c: nil, d: nil, e: nil, f: nil, g: nil, h: nil, i: nil, j: nil)
    orig_new(a, b, c, d, e, f, g, h, i, j)
  end
end

Benchmark.ips do |x|
  x.report('ckw')      { S1.new(a: 1, b: 2, c: 3, d: 4, e: 5, f: 6, g: 7, h: 8, i: 9, j: 10) }
  x.report('rubykw')   { S2.new(a: 1, b: 2, c: 3, d: 4, e: 5, f: 6, g: 7, h: 8, i: 9, j: 10) }
  x.compare!
end; 1

#              rubykw:  4510892.9 i/s
#                 ckw:  1377423.3 i/s - 3.27x  slower

```

----------------------------------------
Misc #19693: Data initialization is significantly slower than Struct
https://bugs.ruby-lang.org/issues/19693#change-103331

* Author: janosch-x (Janosch Müller)
* Status: Closed
* Priority: Normal
----------------------------------------
Maybe there is potential to make it as fast as Struct?

```ruby
require 'benchmark/ips'

S = Struct.new(:a, :b, :c, :d, :e, :f, :g, :h, :i, :j)
D = Data.define(:a, :b, :c, :d, :e, :f, :g, :h, :i, :j)

Benchmark.ips do |x|
  x.report('Struct') { S.new(1, 2, 3, 4, 5, 6, 7, 8, 9, 10) }
  x.report('Data')   { D.new(1, 2, 3, 4, 5, 6, 7, 8, 9, 10) }
  x.compare!
end; 1

# => [...]
# =>             Struct:  6916530.4 i/s
# =>               Data:  1507259.5 i/s - 4.59x  slower
```

-- 
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