Bug #20112
openRactors not working properly in ruby 3.3.0
Description
I recently installed Ruby 3.3.0, and noticed that some of my scripts that use Ractors started to struggle with performance. After doing some benchmarks, I noticed that, while Ractors seem to be working well on Ruby 3.2.2, they're not working properly on 3.3.0.
I'm using Ubuntu 22.04.3 LTS
Here is the benchmark code:
# frozen_string_literal: true
require 'benchmark'
Ractor.new { :warmup } if defined?(Ractor)
Benchmark.bmbm do |x|
x.report("Thread: ") do
threads = []
8.times do |i|
threads << Thread.new do
20000000.times do |j|
((i * 20000000) + j)**2
end
end
end
threads.each(&:join)
end
x.report("Ractor: ") do
ractors = []
0..8.times do |i|
ractors << Ractor.new(i) do |k|
20000000.times do |j|
((k * 20000000) + j)**2
end
end
end
ractors.map(&:take)
end
end
Here is the results for Ruby 3.2.2:
Rehearsal --------------------------------------------
Thread: 7.666909 0.001091 7.668000 ( 7.675266)
Ractor: 19.318528 0.012017 19.330545 ( 2.505888)
---------------------------------- total: 26.998545sec
user system total real
Thread: 7.918141 0.004011 7.922152 ( 7.928772)
Ractor: 19.366414 0.003954 19.370368 ( 2.517993)
Here is the results for Ruby 3.3.0:
Rehearsal --------------------------------------------
Thread: 8.634152 0.010895 8.645047 ( 8.645104)
Ractor: 100.172179 0.035985 100.208164 ( 15.213245)
--------------------------------- total: 108.853211sec
user system total real
Thread: 9.451236 0.004002 9.455238 ( 9.460132)
Ractor: 118.463294 0.119942 118.583236 ( 18.462157)
Updated by hsbt (Hiroshi SHIBATA) 4 months ago
- Status changed from Open to Assigned
- Assignee set to ko1 (Koichi Sasada)
Updated by shadoe (Matthias Mueller) 4 months ago
I stumbled across the same problem. Using the example code taken from https://www.honeybadger.io/blog/ractors/ I also get unexpected results using Ractors in Ruby 3.3.0 in contrast to 3.2.2.
The code:
def tarai(x, y, z) =
x <= y ? y : tarai(tarai(x-1, y, z),
tarai(y-1, z, x),
tarai(z-1, x, y))
require 'benchmark'
Benchmark.bm do |x|
# sequential version
x.report('seq'){ 4.times{ tarai(14, 7, 0) } }
# parallel version
x.report('par'){
4.times.map do
Ractor.new { tarai(14, 7, 0) }
end.each(&:take)
}
end
The results on my machine (Fedora 39, Kernel 6.6.8, AMD Ryzen 3 5300U (4 cores, 8 threads)):
Ruby 3.2.2:
user system total real
seq 70.461697 0.012965 70.474662 ( 71.029432)
par 70.103737 0.009663 70.113400 ( 17.677001)
Ruby 3.3.0:
user system total real
seq 74.018553 0.010097 74.028650 ( 74.329446)
par381.260338 0.070133 381.330471 ( 96.591537)