PLENA Simulator

A Transaction-Level Simulator for the PLENA Accelerator

This repository contains the transaction-level simulator for PLENA (Programmable Long-context Efficient Neural Accelerator).
The simulator models PLENA’s architectural behavior at a high level, enabling rapid exploration of design choices, memory hierarchies, and long-context LLM inference workflows without the overhead of cycle-accurate RTL simulation.

It is primarily used for:

• Architectural design-space exploration
• Memory-system and data-movement analysis
• Rapid prototyping and validation of PLENA execution flows
• Cross-checking performance and scaling trends against RTL and hardware measurements

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PLENA Publication

If you use this simulator in your research, please cite the following paper:

• Combating the Memory Walls: Optimization Pathways for Long-Context Agentic LLM Inference, link

@misc{wu2025combatingmemorywallsoptimization,
  title        = {Combating the Memory Walls: Optimization Pathways for Long-Context Agentic LLM Inference},
  author       = {Haoran Wu and Can Xiao and Jiayi Nie and Xuan Guo and Binglei Lou and Jeffrey T. H. Wong and Zhiwen Mo and Cheng Zhang and Przemyslaw Forys and Wayne Luk and Hongxiang Fan and Jianyi Cheng and Timothy M. Jones and Rika Antonova and Robert Mullins and Aaron Zhao},
  year         = {2025},
  eprint       = {2509.09505},
  archivePrefix= {arXiv},
  primaryClass = {cs.AR},
  url          = {https://arxiv.org/abs/2509.09505}
}

ISA Summary:
View Document on Notion

Prerequisite

nix
direnv 
echo 'eval "$(direnv hook bash)"' >> ~/.bashrc
source ~/.bashrc

Configure your environment

direnv allow
nix develop
git submodule update --init --recursive

Run Behavioral Simulation

just build-behave-sim [ Task to simulate e.g. linear]

Debug mode

just build-behave-sim-debug [ Task to simulate e.g. linear]