This project is a port of Andrej Karpathy's llm.c to Mojo, currently in beta. Visit llm.c for a detailed explanation of the original project.

Note: This project is based on the stable Mojo 25.4 release.

Before using llm.🔥 for the first time, please run the following preparatory commands:

pip install -r requirements.txt
python prepro_tinyshakespeare.py  
python train_gpt2.py

If you don't have it, install pixi:

curl -fsSL https://pixi.sh/install.sh | sh

Start the virtual environment and execute the training program:

pixi shell
mojo train_gpt2.mojo

Note: The first time you run pixi shell, it will automatically install all necessary dependencies defined in pixi.toml.

For a more detailed step-by-step guide including additional setup details and options, please refer to our detailed usage instructions.

Basic benchmark results: (M2 MacBook Pro)

• Below are average training loop times, observed across the various implementations. Please note that these results are intended to provide a general comparison rather than precise, repeatable metrics.

• We are running the OpenMP-enabled train_gpt2.c with 64 threads. (OMP_NUM_THREADS=64 ./train_gpt2)

We ported test_gpt2.c from the original repository to Mojo to validate our port's functionality. For instructions on how to run this test and insights into the results it yields, please see our guide here.

At this stage, there are no plans for further development of this app. It primarily serves as a proof of concept, showcasing Mojo's ability to implement C-like applications in terms of speed and low-level programming. That said, I’m always open to new ideas or collaboration opportunities, so feel free to reach out to discuss ideas.

• 2025.07.27
  • Update to Mojo 25.4
• 2024.12.17
  • Update to Mojo 24.6
• 2024.09.27
  • Experimental Mojo 24.5 nightly version
• 2024.09.24
  • Switch to the Magic package management tool by Modular
• 2024.06.07
  • Update to Mojo 24.4
• 2024.05.04
  • Update to Mojo 24.3
  • Update llm.c changes
• 2024.04.20
  • Further optimization (utilizing unroll_factor of vectorize)
• 2024.04.19
  • test_gpt2.mojo added.
• 2024.04.18
  • Upgraded project status to Beta.
  • Further optimizations of train_gpt2.mojo.
• 2024.04.16
  • Vectorize parameter update
• 2024.04.15
  • Tokenizer Added - train_gpt2.c Update 2024.04.14
  • Bug fix attention_backward
• 2024.04.13
  • Initial repository setup and first commit.

MIT