Joshua Young
@joshuay03.bsky.social
Software Engineer at Buildkite, Rubyist, Rails Issues team member, Puma maintainer, and OSS contributor.
Awesome stuff! 🙌🏽
November 12, 2025 at 7:05 AM
Awesome stuff! 🙌🏽
One last thing I should mention. This doesn't require that your app be ractor safe. The goal is to offload suitable work (just one task for now, I have ideas for at least one more) within the web server itself to ractors, so you can benefit from them without any changes to your app.
5/5
5/5
November 10, 2025 at 5:44 PM
One last thing I should mention. This doesn't require that your app be ractor safe. The goal is to offload suitable work (just one task for now, I have ideas for at least one more) within the web server itself to ractors, so you can benefit from them without any changes to your app.
5/5
5/5
I also need to stop posting stuff like this when it's late for me 😅 I'll come back to answer any questions in the morning. I don't want to divulge too much, especially cause there's a lot more testing I need to do, which could result in major changes before I make it public 🤷🏽♂️
4/5
4/5
November 10, 2025 at 5:44 PM
I also need to stop posting stuff like this when it's late for me 😅 I'll come back to answer any questions in the morning. I don't want to divulge too much, especially cause there's a lot more testing I need to do, which could result in major changes before I make it public 🤷🏽♂️
4/5
4/5
While being inspired by it, I'm making a few design decisions different to Puma that seem to be working out. I won't go into detail yet, but I'll document them eventually. The obvious one is utilising ractors (I'm sure you could guess what for), which Puma should probably also do at some point.
3/5
3/5
November 10, 2025 at 5:44 PM
While being inspired by it, I'm making a few design decisions different to Puma that seem to be working out. I won't go into detail yet, but I'll document them eventually. The obvious one is utilising ractors (I'm sure you could guess what for), which Puma should probably also do at some point.
3/5
3/5
Soooo many disclaimers:
- not a 1:1 comparison, just as close as I could get it for a benchmark baseline
- not a competition, just showing off an exciting experimental working PoC
- just a micro (but not trivial) benchmark using a toy app
- the RHS isn't 100% rack compliant, maybe 60ish%
- etc.
2/5
- not a 1:1 comparison, just as close as I could get it for a benchmark baseline
- not a competition, just showing off an exciting experimental working PoC
- just a micro (but not trivial) benchmark using a toy app
- the RHS isn't 100% rack compliant, maybe 60ish%
- etc.
2/5
November 10, 2025 at 5:44 PM
Soooo many disclaimers:
- not a 1:1 comparison, just as close as I could get it for a benchmark baseline
- not a competition, just showing off an exciting experimental working PoC
- just a micro (but not trivial) benchmark using a toy app
- the RHS isn't 100% rack compliant, maybe 60ish%
- etc.
2/5
- not a 1:1 comparison, just as close as I could get it for a benchmark baseline
- not a competition, just showing off an exciting experimental working PoC
- just a micro (but not trivial) benchmark using a toy app
- the RHS isn't 100% rack compliant, maybe 60ish%
- etc.
2/5
Ah it has `#<<`, but hasn't aliased it to `#send`: github.com/eregon/racto...
Also, probably doesn't matter, but it's the other way around in CRuby i.e., `#<<` is the alias.
Also, probably doesn't matter, but it's the other way around in CRuby i.e., `#<<` is the alias.
ractor-shim/lib/ractor/shim.rb at 69d4d568fdac3f212de3e7d7c3133f31564dc4ec · eregon/ractor-shim
A shim to define Ractor by using Thread, if not already defined - eregon/ractor-shim
github.com
November 1, 2025 at 4:50 AM
Ah it has `#<<`, but hasn't aliased it to `#send`: github.com/eregon/racto...
Also, probably doesn't matter, but it's the other way around in CRuby i.e., `#<<` is the alias.
Also, probably doesn't matter, but it's the other way around in CRuby i.e., `#<<` is the alias.
Has ractor-shim implemented `Ractor::Port#send`? That could be why if not. Ref: docs.ruby-lang.org/en/master/Ra...
class Ractor::Port - Documentation for Ruby 3.5
class Ractor::Port: Port objects transmit messages between Ractors.
docs.ruby-lang.org
November 1, 2025 at 4:45 AM
Has ractor-shim implemented `Ractor::Port#send`? That could be why if not. Ref: docs.ruby-lang.org/en/master/Ra...
I don't have an answer, but I'm figuring that out myself with what I'm building (not ready to share yet). There's a point where the copying/moving/freezing (i.e., message passing) overhead might outweigh the parallelisation benefits. The answer will vary by the payload and the type of work.
October 31, 2025 at 7:14 AM
I don't have an answer, but I'm figuring that out myself with what I'm building (not ready to share yet). There's a point where the copying/moving/freezing (i.e., message passing) overhead might outweigh the parallelisation benefits. The answer will vary by the payload and the type of work.
Yes! I missed that. Clearly my Ractor coverage is lacking... @jhawthorn.com has already sent a fix: github.com/joshuay03/at.... I'll get that merged and released soon.
Fix Ractor safety by jhawthorn · Pull Request #1 · joshuay03/atomic-ruby
Unshareable objects can't be sent to ractors as today these objects are unsafe to concurrently modify. In the future (under Ractor-local GC) this will be even more broken and reading from the o...
github.com
October 31, 2025 at 7:00 AM
Yes! I missed that. Clearly my Ractor coverage is lacking... @jhawthorn.com has already sent a fix: github.com/joshuay03/at.... I'll get that merged and released soon.
2. The thing that clicked for me was when @jhawthorn.com referred to a ractor as a no-GVL block at Rails World. Rather than chucking a whole Rails app in there, you could find CPU intensive code paths that would choke the GVL, and delegate them to a ractor or few. Think complex parsing of strings.
October 30, 2025 at 7:07 AM
2. The thing that clicked for me was when @jhawthorn.com referred to a ractor as a no-GVL block at Rails World. Rather than chucking a whole Rails app in there, you could find CPU intensive code paths that would choke the GVL, and delegate them to a ractor or few. Think complex parsing of strings.
1. Could you clarify? I'm not aware of Ractors needing a C extension to work. Main limitation: C extension gems must mark themselves Ractor-safe. Shareable requirement on init/send exists, plus new semantics like move (may not last: bsky.app/profile/byro...). Docs: docs.ruby-lang.org/en/master/ra...
October 30, 2025 at 7:07 AM
1. Could you clarify? I'm not aware of Ractors needing a C extension to work. Main limitation: C extension gems must mark themselves Ractor-safe. Shareable requirement on init/send exists, plus new semantics like move (may not last: bsky.app/profile/byro...). Docs: docs.ruby-lang.org/en/master/ra...
Ah that’s unfortunate, that does seem like a tricky edge case… Being able to move in my case seems to be quite a bit more performant than both deeply copying (not surprising), and making shareable and duping just the objects I need to mutate in the receiver. Although, I haven’t properly benchmarked.
October 25, 2025 at 12:07 PM
Ah that’s unfortunate, that does seem like a tricky edge case… Being able to move in my case seems to be quite a bit more performant than both deeply copying (not surprising), and making shareable and duping just the objects I need to mutate in the receiver. Although, I haven’t properly benchmarked.
Time for a holiday?
October 7, 2025 at 12:24 PM
Time for a holiday?
Was it the colonoscopy room?
September 22, 2025 at 10:12 AM
Was it the colonoscopy room?
This is from a Datadog APM notebook I used to monitor the impact.
August 30, 2025 at 11:21 PM
This is from a Datadog APM notebook I used to monitor the impact.
Haha yep, I have to remind myself from time to time as well.
August 30, 2025 at 12:25 PM
Haha yep, I have to remind myself from time to time as well.
Yes, at the very end of a before_fork—after doing any necessary closing of connections, shutting down threads, etc.
August 30, 2025 at 10:55 AM
Yes, at the very end of a before_fork—after doing any necessary closing of connections, shutting down threads, etc.