Does the ruby GIL have effect on the processes it starts?

Question

I have noticed that when I use cruby to run a muli-threaded java program via Open3.capture3('java -jar multi-threaded.jar'), most java threads are idle and the CPU is only busy on a single core. However, if I run the same javaprogram from bash, the CPU has near 100% utilization.

Does the cruby GIL have an effect on programs run by capture3?

Answer 1

No. First off, the YARV Giant VM Lock (GVL) only prevents multiple Ruby threads from entering the bytecode interpreter at the same time. In YARV, Open3::capture3 is written in C, not Ruby, so the GVL doesn't even apply.

Secondly, the Java process isn't a thread, it's an entirely separate process. It doesn't care a bit what YARV's threading implementation does, because it's a process, not a thread.