Reworking Memory Management in CRuby

https://railsatscale.com/2025-09-16-reworking-memory-management-in-cruby/

by ksec • 9 months ago

38 8 9 months ago

Alifatisk• 9 months ago

One of the superpowers of MMTk is that it supports parallelism in the garbage collector. Unlike Ruby’s default garbage collector

Wow

sebiw• 9 months ago

"Wow" as in "why doesn't Ruby have that already" or as in "parallelism will be great"? :-)

Thev00d00• 9 months ago

Why not both :D

Lio• 9 months ago

When we say "Ruby" doesn't have parallel GC we're really just talking about MRI cRuby.

Both the JRuby and TruffleRuby implemenations have had parellel GC for a very long time.

I think Peter Zhu work on cRuby has been brilliant here and is really appreciated.

pjmlp• 9 months ago

As historical background information, MMTk was initially implemented in Java, and used on the JikesRVM VM, one of the very first bootstraped Java implementations.

https://www.jikesrvm.org/UserGuide/MMTk/index.html

Eventually they rewrote it in Rust,

https://www.mmtk.io/

Thus it is much more than the 5 years mentioned on the post, that only covers the rewrite.

schneems2• 9 months ago

It’s not even remotely close to the main point of the article but: I really like the Chris Seaton callout. I talked about this initiative with him the RubyConf before he passed.

Open Source contributors and maintainers feel that there is a constant pressure to be producing. That somehow our worth is somehow only as good as our recent patches. That note says to me: that’s not the case. That even after the contributions stop, or we do, that our efforts and impacts are felt and remembered.

ksec• 9 months ago

I really like the Chris Seaton callout

I miss him. And I really hope someday TruffleRuby will succeed and become mainstream or at least 2nd only to Cruby.

schneems2• 9 months ago

I miss him too. We knew each other online for some time, but that was the first time I ever met him in person. I came back and couldn’t stop talking about him to my wife when she asked how the conf went. Truly an inspiring experience.

I hope truffle ruby does well, too. But even if it doesn’t, he’s still made an impact on me, and on the community. I told him “thank you” to his face when we met. I also wish I could have also somehow let him know my thanks and appreciation was unconditional.

Reworking Memory Management in CRuby

Related Stories