Issue #20338 has been updated by kjtsanaktsidis (KJ Tsanaktsidis).
I haven’t looked at this at all myself, but it tingled my “this is familiar” sense. Is
this the same problem as
https://github.com/ruby/ruby/pull/10151 ?
----------------------------------------
Bug #20338: calling new has regressed allocations over past few ruby releases
https://bugs.ruby-lang.org/issues/20338#change-107260
* Author: fablestales (Fable Tales)
* Status: Open
* Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN
----------------------------------------
Given this script:
```
class Foo
def initialize(**kwargs)
end
end
class Bar
def initialize(y:)
end
end
b = GC.stat[:total_allocated_objects]
1000.times {
Foo.new(y:1)
}
p GC.stat[:total_allocated_objects]-b
b = GC.stat[:total_allocated_objects]
1000.times {
Bar.new(y:1)
}
p GC.stat[:total_allocated_objects]-b
```
On Ruby 3.2 it prints
```
(fable-3_3_dead_with_patches) $ ruby --version
ruby 3.2.3 (2024-01-18 revision 52bb2ac0a6) [arm64-darwin23]
(fable-3_3_dead_with_patches) $ ruby hi.rb
3006
2005
```
On Ruby 3.3 it prints:
```
((HEAD detached at v3_3_0)) $ ./ruby --version
ruby 3.3.0 (2023-12-25 revision 5124f9ac75) [arm64-darwin23]
((HEAD detached at v3_3_0)) $ ./ruby hi.rb
3008
3005
```
On master:
```
(master) $ git rev-parse HEAD
83618f2cfa004accdd1514de7dcbba291aa7e831
(master) $ ./ruby --version
ruby 3.4.0dev (2024-03-14T12:33:30Z master 83618f2cfa) [arm64-darwin23]
(master) $ ./ruby hi.rb
3006
4005
```
so that is: since Ruby 3.2 `.new`ing an object with static keyword args has grown from 2
allocations per object to 4 allocations per object.
I have a pull request which introduces a new instruction to the VM `opt_new` which
basically inlines calling allocate and initialize directly, avoiding a lot of what is
causing these extra objects to be allocated. My PR is here:
https://github.com/ruby/ruby/pull/10254. With my patch the script prints 2006 and 1005
respectively. This is the smallest number of objects that _can_ be allocated for such
calls.
--
https://bugs.ruby-lang.org/