From: "alanwu (Alan Wu) via ruby-core" <ruby-core@ml.ruby-lang.org>
To: ruby-core@ml.ruby-lang.org
Cc: "alanwu (Alan Wu)" <noreply@ruby-lang.org>
Subject: [ruby-core:117283] [Ruby master Bug#20338] certain **kwsplat calls have regressed allocations over past few ruby releases
Date: Thu, 21 Mar 2024 17:33:00 +0000 (UTC) [thread overview]
Message-ID: <redmine.journal-107409.20240321173259.53225@ruby-lang.org> (raw)
In-Reply-To: redmine.issue-20338.20240314140511.53225@ruby-lang.org
Issue #20338 has been updated by alanwu (Alan Wu).
Subject changed from calling new has regressed allocations over past few ruby releases to certain **kwsplat calls have regressed allocations over past few ruby releases
Status changed from Open to Closed
After commit:aceee71c35e0b387691836e756b4e008efd84cf1 and commit:15dc3aaa311b32203d8ffb414bcf9b8e55ce5691, it's now back down to 3.2 levels on the master branch:
```
$ ./miniruby -v test.rb
ruby 3.4.0dev (2024-03-21T17:20:32Z master 15dc3aaa31) [arm64-darwin23]
3006
2005
```
The extra allocations were general issues with kwsplat calls which `Class#new` uses internally.
----------------------------------------
Bug #20338: certain **kwsplat calls have regressed allocations over past few ruby releases
https://bugs.ruby-lang.org/issues/20338#change-107409
* Author: fablestales (Fable Tales)
* Status: Closed
* 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/
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prev parent reply other threads:[~2024-03-21 17:33 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-14 14:05 [ruby-core:117169] [Ruby master Bug#20338] calling new has regressed allocations over past few ruby releases fablestales (Fable Tales) via ruby-core
2024-03-14 14:12 ` [ruby-core:117170] " kjtsanaktsidis (KJ Tsanaktsidis) via ruby-core
2024-03-14 14:15 ` [ruby-core:117171] " kjtsanaktsidis (KJ Tsanaktsidis) via ruby-core
2024-03-21 17:33 ` alanwu (Alan Wu) via ruby-core [this message]
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