legion VS Zulip

I work on a distributed runtime system for heterogeneous supercomputers [1].

As an example of the sort of bug we regularly deal with, I am at this exact moment tracking down a freeze that occurs on 8,192 nodes of a supercomputer [2]. That means I'm using about 64,000 GPUs and about half a million CPU cores. The smallest node count I've seen my issue is 2,048 nodes and at that scale it only happens about 10% of the time.

We've been debating internally whether Antithesis could help us or not. On the one hand, the fuzzing to explore the state space, and deterministic reproduction, are exactly what we want. On the other hand, we believe our state space is much larger than what you see in a typical distributed database. (And not just because of the sheer scale of things, but even on a single node we have state machines with order hundreds to thousands of states in them.) Based on the post here and the "scenario" count explored in CouchDB, I'm not convinced you'd be able to handle us. :-)

I'd be curious what you think. Happy to discuss here, or contact info in profile.

[1]: https://legion.stanford.edu/

[2]: https://www.olcf.ornl.gov/frontier/

Parallelism in CS is a bit like security in CS. People know it matters in the abstract senses but you really only get into it if you look for the training specifically. We're getting better at both over time: just as more languages/libraries/etc. are secure by default, more now are parallel by default. There's a ways to go, but I'm glad we didn't do this prematurely, because the technology has improved a lot in the last decade. Look for example at what we can do (safely!) with Rayon in Rust vs (unsafely!) with OpenMP in C++.

And there are things even further afield like what I work on [1][2][3].

[1]: https://legion.stanford.edu/

[2]: https://regent-lang.org/

[3]: https://github.com/nv-legate/cunumeric

Chapel has at least several full-time developers at Cray/HPE and (I think) the US national labs, and has had some for almost two decades. That's much more than $100k.

Chapel is also just one of many other projects broadly interested in developing new programming languages for "high performance" programming. Out of that large field, Chapel is not especially related to the specific ideas or design goals of Mojo. Much more related are things like Codon (https://exaloop.io), and the metaprogramming models in Terra (https://terralang.org), Nim (https://nim-lang.org), and Zig (https://ziglang.org).

But Chapel is great! It has a lot of good ideas, especially for distributed-memory programming, which is its historical focus. It is more related to Legion (https://legion.stanford.edu, https://regent-lang.org), parallel & distributed Fortran, ZPL, etc.

I should also note that there is Pygion if you want to use Python. Not a lot of great reference material right now, but there's the paper:

https://legion.stanford.edu/pdfs/pygion2019.pdf

And code samples:

https://github.com/StanfordLegion/legion/tree/stable/binding...

We use PyPy for performing verification of our software stack [1], and also for profiling tools [2]. The verification tool is basically a complete reimplementation of our main product, and therefore encodes a massive amount of business logic (and therefore difficult to impossible to rewrite in another language). As with other users, we found the switch to PyPy was seamless and provides us with something like a 2.5x speedup out of the box, with (I think) higher speedups in some specific cases.

We eventually rewrote the profiler tool in Rust for additional speedups, but as mentioned for the verification engine, it's probably too complicated to ever do that so we really appreciate drop-in tools like PyPy that can speed up our code.

[1]: https://github.com/StanfordLegion/legion/blob/master/tools/l...

[2]: https://github.com/StanfordLegion/legion/blob/master/tools/l...

Legion is also doing something like that: https://legion.stanford.edu/

If you really want to dig into it you can read up on the tutorials and/or papers from the Legion project: https://legion.stanford.edu/

But briefly, these task-based programs preserve sequential semantics. That means (whatever the system actually does when running your program), as long as you follow the rules, the parallelism should be invisible to the execution of the program.

Computer Science Research Dept., SLAC National Accelerator Laboratory | Research Scientist / Engineer | Menlo Park, CA or REMOTE, VISA | Full Time

We're a research group within SLAC, headed by Alex Aiken (https://theory.stanford.edu/~aiken/). We focus on fundamental CS research that has the potential to impact science, mainly in the areas of high-performance and distributed computing, programming languages, compilers, networks, operating systems, etc. One of our major projects is Legion, a forward-looking programming system for distributed computing (https://legion.stanford.edu/). Legion has been used to create new programming languages (https://regent-lang.org/), seamless distributed NumPy (https://developer.nvidia.com/cunumeric), and a drop-in replacement for Keras and PyTorch (https://flexflow.ai/), among many other things.

We are looking for strong scientists and engineers to join our group. For clarity (because these terms vary by industry/company), scientists mainly focus on producing research results (e.g., papers and research software) while engineers mainly focus on software development and deliverables (e.g., system or application implementation). For scientist positions please expect to provide a CV with relevant publications.

The official application links are below, but please feel free to contact me directly if you have questions. (My HN username @slac.stanford.edu)

Scientist (Computer Science):

https://erp-hprdext.erp.slac.stanford.edu/psp/hprdext/EMPLOY...

Engineer (Computer Science):

https://erp-hprdext.erp.slac.stanford.edu/psp/hprdext/EMPLOY...

We've had some reports that the application site doesn't work well in Google Chrome. You might want to apply in Firefox.

There are some points in the middle, but it's rare. I worked on one of these [1]. We've been building the system for just over ten years, and are starting to see some truly killer apps being built on top of it [2, 3].

While it has some great benefits once you arrive, the upfront costs are enormous. You basically need to find a funding source (or sources) that will pay for this product while you're building it. Also, in order for the research payoff to be worth it, you need both the product itself, and subsequent innovations it enables, to be research-worthy. Not all areas of research can support this. On top of it all, even when you do this, you'll still spend years of effort in activities that are essentially not research. You're basically responsible for all of your own customer support, sales, marketing, etc.---like a startup, but without the financial upside if you succeed. Yes there is recognition and so on, but the payoffs aren't as dramatic. Most people aren't ready to commit to this path.

Keep in mind that you can't build this in 5 years either. So a single generation of PhD students can't get it done. The only reason we were successful is because the key staff on the project stuck around for 5+ years after their PhDs because we all believed in doing the work.

Given all that, I don't hold it against people at all who just want to build prototypes and then move on to the next thing. It's way less risky and higher reward relative to the costs.

[1]: https://legion.stanford.edu/

[2]: https://flexflow.ai/

[3]: https://developer.nvidia.com/cunumeric

Zulip — Real-time chat with a unique email-like threading model. The free plan includes 10,000 messages of search history and File storage up to 5 GB. also, it provides a self-hostable open-source version.

(1) Zulip Chat - https://zulip.com/ - seems to be reasonably popular, but more people should know about it

I’ve been using it for over 5 years now [1], and it’s as good as ever. It’s way faster than any other chat app I’ve used. It has a good UI and conversation model. It has a simple and functional API that lets me curl threads and write blog posts based on them.

(only problem is that I Ctrl-+ in my browser to make the font bigger – I think it’s too dense for most people)

(2) re2c regex to state machine compiler - https://re2c.org

A gem from the 90’s, which people have done a great job maintaining and improving (getting Go and Rust target support in the last few years). I started using it in 2016, and used for a new program a few months ago. I came to the conclusion that it should have been built into C, because C has shitty string processing – and Ken Thompson both invented C AND brought regular languages to computing !!

In comparison, treesitter lexers are very low level, fiddly, and error prone. I recently saw dozens of ad hoc fixes to the tree-sitter-bash lexer, which is unsurprising if you look at the structure of the code (manually crawling through backslashes and braces in C).

https://github.com/tree-sitter/tree-sitter-bash/blob/master/...

These fixes are definitely appreciated, but I think it indicates a problem with the model itself.

(based on https://lobste.rs/s/endspx/software_you_are_thankful_for#c_y...)

[1] https://www.oilshell.org/blog/2018/04/26.html

A few more truly in the vibe of open source projects not advertising their hosting providers: https://plane.so/ , https://element.io/ , https://www.loomio.com/ , https://zulip.com/ , and it keeps going... Very few open source projects, in the FOSS sense, are advertising their hosting provider.

I was so excited to see this happen!

I'm not a customer of yours, but your blog posts inspired me a lot. Your journey through quitting caffeine is a great and heartening read.

I've got two things to say;

1) Will you consider source-availabling the web portal (app.keygen.sh) too? Some enterprises could use it for easy management/support for custoner's licenses. Although now that I think about it, it could also discourage custom, more suitable implementations for each use-case... I'm torn on this one. I would like to see it available on GitHub too just out of curiosity too. It's very beautiful.

2) For a team + customers' chat, I cannot recommend Zulip enough. It's a joy to use and has the most innovative chat system I've ever seen. https://zulip.com

I hope your business keeps prospering!

Zulip | Senior Flutter Engineer | REMOTE or San Francisco | Full-time | https://zulip.com/

At Zulip, we’re out to build the world’s best collaboration platform, and we’re committed to keeping it 100% open source. Zulip is the only modern team chat app that is designed for both live and asynchronous conversations. Our product serves as the communication hub for businesses, open-source projects, educators and communities around the world.

We're building the next generation of Zulip's mobile apps in Flutter. We're looking for a senior engineer with Flutter experience to join our small core team and help define the future of team chat. Our Flutter prototype is just a few months old, so this is a greenfield opportunity to help shape the app's architecture from early on.

For full details, check out https://zulip.com/jobs/. Apply at [email protected].

Anyways, I'm an internet stranger, not a social media expert. So let me know what you all think. And if we make a discord or zulip or something to make this a reality, let me know and I'd love to help any way I can.