[agibsonccc]

It's still pretty early days for ray yet. That being said, spark never really got the hang of doing machine learning properly. It "works" but not for newer workloads which ray is trying to support.

It's good someone is building a company around it. I could see them building services on top of it and build a SAAS like databricks did with spark.

I'll be curious to see how ray matures.

[choppaface]

I agree that ML on Spark was only a limited hit—- iterative jobs would actually be feasible versus Hadoop—- I still have yet to find a better ETL and SQL tool, and that’s a big part of most ML projects.

I’m worried about Ray as a SAAS Co because so far it looks to me like they’re riding reinforcement learning hype. They’d need to really penetrate the users of Horovod and Tensorflow Distributed to get beyond a beach head. And what if TPUs and Cerebras become more common? Because then the maker for multi-machine workloads becomes smaller (definitely not zero though).

[agibsonccc]

Your concerns are right on point. I agree that spark is a great sql/etl tool. My thinking was on the "math execution" part. Ray is able to doa bit more there. I do feel like there is a bit of hype riding going on here as well.

One interesting thing that could happen is the hardware gets better, and then these distributed schedulers might not be able to keep up with all the different options on the market.

There is also the tension of the hardware vendors wanting to give away things that only run on their chips vs the software makers who want things to run on every chip. It seems like there will be a lot of competition among the various infra players in the next few years now that nvidia is starting to have real competition now (even if it's not big yet)

[choppaface]

Just to qualify that "math execution" part, the beauty of Ray is that you get threadpool-like features to speed up arbitrary python code. So not just parallelism, but state/variable sharing for relatively small data. So this is great for some optimizers and definitely RL (where your "math" is some really complicated simulation / loss logic), but Ray wouldn't make much sense for BLAS stuff. Am I missing something here?

Ray shows expertise in multi-machine that's lacking in stuff like Jax, Tensorflow, and PyTorch. Horovod nailed down a lot of the performance issues for SGD in particular, but is missing the sort of rapid deployment / distribution stuff in Ray. If only they could all work together ...