LLM Post Training

Modern post-training can involve supervised finetuning (SFT), preference optimisation, RL training using various policy optimisation algorithms and distillation. Fun commentary on the meme by Nathan Lambert A good analogy I think of different stages is Pretraining: Learning language, knowledge and task representations through next-token prediction. SFT: Adapting a pretrained model to imitate desired responses, follow instructions and produce task-specific output formats.A Preference optimisation: Learn which responses should be preferred over others. RL or verifiable RL: It takes one step further, optimizing model behaviour using rewards, preferences or verifiable outcomes rather than only imitating reference responses. Distillation: Learn from the behaviour of a stronger teacher model, rather than only from fixed target responses or scalar rewards. The Smol Training Playbook ...

October 3, 2026 · 13 min · 2665 words

Where vLLM Cold-Start Time Goes on GKE?

Measuring vLLM cold-start bottlenecks on GKE and evaluating ways to reduce time to first request.

April 11, 2026 · 12 min · 2519 words

Pipeline Parallelism Revisited - Implementations using PyTorch

Implementing and profiling pipeline parallelism techniques using PyTorch

March 13, 2026 · 26 min · 5519 words

ZeRO Sharding Revisited - Implementations using PyTorch

Implement ZeRO sharding strategies using PyTorch

February 28, 2026 · 23 min · 4762 words

Data Parallelism Revisited - Implementations using PyTorch

Implement various data parallelism strategies using PyTorch

December 28, 2025 · 21 min · 4273 words