xAI Senior Model Engineer at xAI focusing on RL inference infrastructure to optimize low precision RL training and inference. Responsible for designing and optimizing inference stacks and addressing performance bottlenecks.
Responsibilities
Design and optimize our inference stack for all shapes of RL workloads at SpaceXSI, from small scale ablations to production training runs
Analyze, profile and address performance bottlenecks in large scale RL systems
Work closely with the modeling team to efficiently implement novel RL techniques and algorithms
Qualification
Experience training large models (eExperience in buildingExperience in LLM inference
Required
Experience writing production-quality code in Python, PyTorch, JAX, Rust, or C++
Experience training large models (e.g., pre-training, post-training, fine-tuning, or RL training of neural networks with 1B+ parameters)
Preferred
Experience in building, debugging, and optimizing efficiency of large-scale distributed systems
Experience in LLM inference
Strong knowledge in quantization and numerics in LLM inference and training
Experience in developing inference engines, e.g. SGLang, vLLM
Willingness to dive deep and solve hardcore problems at all levels of the stack
