Summary

Marshal.load shows a 2.9x performance regression in JRuby 10.0.2.0 compared to JRuby 1.7.27.

Benchmark Results

The regression is specifically in Marshal.load - dump performance is actually slightly improved.

Test Code

medium_data = {
  :id => 1,
  :name => "test" * 100,
  :values => (1..1000).to_a,
  :nested => { :a => 1, :b => 2, :c => (1..100).to_a }
}

# Load only benchmark
dumped = Marshal.dump(medium_data)
1000.times { Marshal.load(dumped) }

Impact

This affects applications that:

• Use Marshal for caching (Rails cache stores)
• Perform inter-process communication via Marshal
• Deserialize stored Ruby objects
• Use sidekiq/resque job serialization

Environment

• JRuby 10.0.2.0 with Java 21 (Temurin)
• JRuby 1.7.27 with Java 8 (Corretto)
• macOS Darwin 25.1.0