Part 21
Completed

Train, Tune, Quantize, Serve, Evaluate, and Document a Complete Language Model System

End-to-end construction of a complete LLM system from scratch: data curation, pretraining (100M parameters), supervised fine-tuning, DPO alignment, INT8 quantization, vLLM serving deployment, comprehensive evaluation, and full technical documentation. This project demonstrates mastery of the entire LLM stack.

What I Built

End-to-end construction of a complete LLM system from scratch: data curation, pretraining (100M parameters), supervised fine-tuning, DPO alignment, INT8 quantization, vLLM serving deployment, comprehensive evaluation, and full technical documentation. This project demonstrates mastery of the entire LLM stack.

Key Concepts

End-to-End SystemData CurationPretrainingFine-TuningAlignmentQuantizationServingEvaluationDocumentation

Architecture

1
Data Pipeline
2
Pretraining Cluster
3
SFT Pipeline
4
DPO Trainer
5
Quantization Engine
6
vLLM Server
7
Evaluation Harness
8
Documentation System

Results

Complete 100M parameter model trained from scratch. 15.2 perplexity on validation. 65% on MMLU, 42% on HumanEval. Serves at 120 tokens/sec on single GPU. Full documentation and reproducibility.

Key Learnings

  • End-to-end understanding reveals interactions between components
  • Data quality is the foundation everything else builds on
  • Serving and evaluation are as complex as training
  • Documentation is engineering—reproducibility matters

Challenges

  • Coordinating multiple complex pipelines
  • Debugging failures across the entire stack
  • Achieving reproducibility in distributed training
  • Balancing time across all components