server VS Megatron-LM

This is very interesting but many of the motivations listed are far better served with alternate approaches.

For "remote" model training there is NCCL + Deepspeed/FSDP/etc. For remote inferencing there are solutions like Triton Inference Server[0] that can do very high-performance hosting of any model for inference. For LLMs specifically there are nearly countless implementations.

That said, the ability to use this for testing is interesting but I wonder about GPU contention and as others have noted the performance of such a solution will be terrible even with relatively high speed interconnect (100/400gb ethernet, etc).

NCCL has been optimized to support DMA directly between network interfaces and GPUs which is of course considerably faster than solutions like this. Triton can also make use of shared memory, mmap, NCCL, MPI, etc which is one of the many tricks it uses for very performant inference - even across multiple chassis over another network layer.

[0] - https://github.com/triton-inference-server/server

As always, it depends a lot on what you're doing, and a lot of people are using Python for AI.

One of the drawbacks of multi-processing versus multi-threading is that you cannot share memory (easily, cheaply) between processes. During model training, and even during inference, this becomes a problem.

For example, imagine a high volume, low latency, synchronous computer vision inference service. If you're handling each request in a different process, then you're going to have to jump through a bunch of hoops to make this performant. For example, you'll need to use shared memory to move data around, because images are large, and sockets are slow. Another issue is that each process will need a different copy of the model in GPU memory, which is a problem in a world where GPU memory is at a premium. You could of course have a single process for the GPU processing part of your model, and then automatically batch inputs into this process, etc. etc. (and people do) but all this is just to work around the lack of proper threading support in Python.

By the way, if anyone is struggling with these challenges today, I recommend taking a peek at nvidia's [triton](https://github.com/triton-inference-server/server) inference server, which handles a lot of these details for you. It supports things like zero-copy sharing of tensors between parts of your model running in different processes/threads and does auto-batching between requests as well. Especially auto-batching gave us big throughput increase with a minor latency penalty!

I am wondering what is the best / most cost-efficient way to serve llama V2. - llama.cpp (is it production ready or just for playing around?) ? - Triton inference server ? - HF text generation inference ?

For inference of CNNs, memory should really not be an issue. If it is a software engineering problem, not a hardware issue. FP16 or Int8 for weights is fine and weight size won’t increase due to the high resolution. And during inference memory used for hidden layer tensors can be reused as soon as the last consumer layer has been processed. You likely using something that is designed for training for inference and that blows up the memory requirement, or if you are using TensorRT or something like that, you need to be careful to avoid that every tasks loads their own copy of the library code into the GPU. Maybe look at https://github.com/triton-inference-server/server

I am looking for something like [Triton Inference Server](https://github.com/triton-inference-server/server) or [TFX Serving](https://www.tensorflow.org/tfx/guide/serving), but in Rust. I came across [Orkon](https://github.com/vertexclique/orkhon) which seems to be dormant and a bunch of examples off of the [Awesome-Rust-MachineLearning](https://github.com/vaaaaanquish/Awesome-Rust-MachineLearning)

https://github.com/NVIDIA/Megatron-LM

This is probably a good baseline to start thinking about LLM training at scale.

This 20B model was trained on the same datasets as its predecessor, aptly named The Pile. Furthermore, the libraries Megatron and DeepSpeed were used to achieve better computing resource utilization, and eventually GPT-NeoX evolved into its own framework for training other LLMs. It was used, for example, as the foundation for Llemma, an open-source model specializing on theorem proving.

Deepspeed Megatron-LM

GPU cluster scaling has come a long way. Just checkout the scaling plot here: https://github.com/NVIDIA/Megatron-LM

I found their code that the softmax function conduct all-reduce before they work.

Google's PaLM, Facebook's LLaMA, Nvidia's Megatron, I am missing some surely and Apple sure has something cooking as well but these are the big ones, of course none of them are publicly available, but research papers are reputable. All of the ones mentioned should beat GPT-3 although GPT-3.5 (chatGPT) should be bit better and ability to search (Bing) should level the playing field even further, but Google's PaLM with search functionality should be clearly ahead. This is why people are excited about GPT-4, GPT-3 was way ahead of anyone else when it came out but others were able to catch up since, we'll see if GPT-4 will be another bing jump among LLMs.

Found relevant code at https://github.com/nvidia/megatron-lm + all code implementations here