A feature which originated in 9.3 (#6422) seems to have caused a 20x performance degradation in micro-benchmarks compared to 9.2.
This has been observed in production as threads pile up due synchronization and the extra overhead each <init> call has.
The following script demonstrates a Ruby sub-class of a Java class which will have poor class.new performance :
puts RUBY_DESCRIPTION + "\n\n"
require 'benchmark'
class RubyList < java.util.ArrayList
def initialize(*args) # method's actual logic is irrelevant here
# the idea is simply that more instructions will slow-down execution more
foo = args.first.is_a?(NilClass) && args.shift
bar = args.first.is_a?(String) ? args.shift : self.class.name
if foo
super_args = args.dup.to_java(:string)
elsif bar
super_args = [bar, *args]
else
super_args = args
end
super(super_args)
end
end
time = Benchmark.realtime do
threads = []
1000.times do |i|
threads << Thread.start do
('a'..'z').each { |c| 1000.times { RubyList.new(i.to_s, c) } }
end
end
threads.each(&:join)
end
puts "1 RubyList.new(...) elapsed real-time: #{time}"
time = Benchmark.realtime do
threads = []
1000.times do |i|
threads << Thread.start do
('a'..'z').each { |c| 1000.times { RubyList.new } }
end
end
threads.each(&:join)
end
puts "2 RubyList.new elapsed real-time: #{time}"$ jruby slow_java_super.rb
jruby 9.2.20.0 (2.5.8) 2021-11-02 1a3255440b OpenJDK 64-Bit Server VM 11.0.14.1+1 on 11.0.14.1+1 +jit [linux-x86_64]
1 RubyList.new(...) elapsed real-time: 3.4137503600068158
2 RubyList.new elapsed real-time: 2.6153695250031888
$ jruby slow_java_super.rb
jruby 9.3.10.0 (2.6.8) 2023-02-01 107b2e6697 OpenJDK 64-Bit Server VM 11.0.14.1+1 on 11.0.14.1+1 +jit [x86_64-linux]
1 RubyList.new(...) elapsed real-time: 54.96447179099778
2 RubyList.new elapsed real-time: 54.98580553600186
A feature which originated in 9.3 (#6422) seems to have caused a 20x performance degradation in micro-benchmarks compared to 9.2.
This has been observed in production as threads pile up due
synchronizationand the extra overhead each<init>call has.The following script demonstrates a Ruby sub-class of a Java class which will have poor
class.newperformance :