From: "luke-gru (Luke Gruber) via ruby-core" <ruby-core@...>
Date: 2023-01-24T17:42:03+00:00
Subject: [ruby-core:112012] [Ruby master Bug#19288] Ractor JSON parsing significantly slower than linear parsing

Issue #19288 has been updated by luke-gru (Luke Gruber).


> It has many issues as can be found on this bug tracker and when using it and as the warning says (Also there are many implementation issues.).

I think the implementation issues are solvable but the bigger picture issue of adoption is of course up in the air. IMO if are allowed to have an API, for example, of Ractor.disable_isolation_checks! { ... } for use around thread-safe code, that would be a big win in my book.

Also about the test-suite, I do want to add in-process ractor tests. I hope the ruby core team isn't against it.



----------------------------------------
Bug #19288: Ractor JSON parsing significantly slower than linear parsing
https://bugs.ruby-lang.org/issues/19288#change-101445

* Author: maciej.mensfeld (Maciej Mensfeld)
* Status: Open
* Priority: Normal
* ruby -v: ruby 3.2.0 (2022-12-25 revision a528908271) [x86_64-linux]
* Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN
----------------------------------------
a simple benchmark:

```ruby
require 'json'
require 'benchmark'

CONCURRENT = 5
RACTORS = true
ELEMENTS = 100_000

data = CONCURRENT.times.map do
  ELEMENTS.times.map do
    {
      rand => rand,
      rand => rand,
      rand => rand,
      rand => rand
    }.to_json
  end
end

ractors = CONCURRENT.times.map do
  Ractor.new do
    Ractor.receive.each { JSON.parse(_1) }
  end
end

result = Benchmark.measure do
  if RACTORS
    CONCURRENT.times do |i|
      ractors[i].send(data[i], move: false)
    end

    ractors.each(&:take)
  else
    # Linear without any threads
    data.each do |piece|
      piece.each { JSON.parse(_1) }
    end
  end
end

puts result
```

Gives following results on my 8 core machine:

```shell
# without ractors:
  2.731748   0.003993   2.735741 (  2.736349)

# with ractors
12.580452   5.089802  17.670254 (  5.209755)
```
I would expect Ractors not to be two times slower on the CPU intense work.





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