[ruby-core:112348] [Ruby master Bug#19424] Significant performance decreases in `OpenStruct#marshal_load` in Ruby 3.0 and 3.1

10 Feb 2023

      Issue #19424 has been updated by jeremyevans0 (Jeremy Evans).

byroot (Jean Boussier) wrote in #note-5:
...
That Ruby 3.0+ difference is likely due to the `if defined? Ractor` branching in the gem. On 3.0 it has to do even more work to make the defined methods Ractor safe.
Presumably that is not something we would want to revert.

I checked and performance with the 2.7 version of ostruct remains the same in Ruby 3.0 and 3.1:

```
ruby 2.7.7p221 (2022-11-24 revision 168ec2b1e5) [x86_64-openbsd]
["OpenStruct::VERSION", "0.2.0"]
                           user     system      total        real
OpenStruct dump        0.540000   0.000000   0.540000 (  0.525649)
OpenStruct load        0.400000   0.000000   0.400000 (  0.374714)
OpenStruct new         0.120000   0.000000   0.120000 (  0.122805)
ruby 3.0.5p211 (2022-11-24 revision ba5cf0f7c5) [x86_64-openbsd]
["OpenStruct::VERSION", "0.2.0"]
                           user     system      total        real
OpenStruct dump        0.520000   0.000000   0.520000 (  0.533818)
OpenStruct load        0.500000   0.000000   0.500000 (  0.489260)
OpenStruct new         0.130000   0.000000   0.130000 (  0.132554)
ruby 3.1.3p185 (2022-11-24 revision 1a6b16756e) [x86_64-openbsd]
["OpenStruct::VERSION", "0.2.0"]
                           user     system      total        real
OpenStruct dump        0.560000   0.000000   0.560000 (  0.560805)
OpenStruct load        0.510000   0.000000   0.510000 (  0.515713)
OpenStruct new         0.150000   0.000000   0.150000 (  0.134401)
```

The only issue is the version of ostruct that shipped with Ruby 2.7 (0.2.0) is not available as a gem, so users that want to use that version to improve load/new performance cannot do so.  However, the ostruct 0.1.0 release that shipped with Ruby 2.6 is available as a gem and offers similar load/new performance.

----------------------------------------
Bug #19424: Significant performance decreases in `OpenStruct#marshal_load` in Ruby 3.0 and 3.1
https://bugs.ruby-lang.org/issues/19424#change-101792

* Author: sumitdey035 (Sumit Dey)
* Status: Open
* Priority: Normal
* ruby -v: 3.1.2
* Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN
----------------------------------------
I can see degradation in **Marshal load** only in Ruby 3.1.2 compared to 2.7.4
Processing time increased by 200%(2.4 sec to 4.3 sec)
Memory allocation increased by 600%(6500001 to 39000004)

```
require 'benchmark'
require 'ostruct'

N_OJ = 500_000

ex_HASH = { 'one' => 1, 'array' => [ true, false ] }
ex_JSON = '{ "one": 1, "array": [ true, false ] }'

ex_STRUCT = OpenStruct.new( one: 1, hash: ex_HASH, array: [ true, false ] )
ex_MARSHAL = "\x04\bU:\x0FOpenStruct{\b:\bonei\x06:\thash{\aI\"\bone\x06:\x06ETi\x06I\"\narray\x06;\bT[\aTF:\narray[\aTF"

"-----------------Ruby #{system("rbenv version")}----------------"

Benchmark.bm(20) do |x|
  x.report('native marshal dump') do
    N_OJ.times do
      y = Marshal.dump(ex_STRUCT)
    end
  end

  x.report('native marshal load') do
    N_OJ.times do
      y = Marshal.load(ex_MARSHAL)
    end
  end

  start_memory = GC.stat[:total_allocated_objects]
  N_OJ.times do
    y = Marshal.dump(ex_STRUCT)
  end
  end_memory = GC.stat[:total_allocated_objects]
  print "Marshal dump memory allocation- #{end_memory - start_memory}\n"

  start_memory = GC.stat[:total_allocated_objects]
  N_OJ.times do
    y = Marshal.load(ex_MARSHAL)
  end
  end_memory = GC.stat[:total_allocated_objects]
  print "Marshal load memory allocation- #{end_memory - start_memory}\n"
end```

**Benchmark and Memory consumption result**
![](Screenshot 2023-02-07 at 1.04.49 PM.png)

---Files--------------------------------
Screenshot 2023-02-07 at 1.04.49 PM.png (184 KB)

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