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[2602.18568] RPU -- A Reasoning Processing Unit
Summary
The paper introduces the Reasoning Processing Unit (RPU), a novel chiplet-based architecture designed to overcome memory bandwidth limitations in large language model (LLM) applications, enhancing performance and efficiency.
Why It Matters
As LLMs become more prevalent, optimizing their performance is crucial. The RPU addresses significant bottlenecks in memory bandwidth, which can lead to improved inference speeds and reduced energy consumption, making it relevant for advancements in AI hardware architecture.
Key Takeaways
- RPU offers a solution to the memory wall challenge faced by LLMs.
- It features a Capacity-Optimized High-Bandwidth Memory (HBM-CO) for better energy efficiency.
- The architecture separates memory, compute, and communication pipelines to optimize performance.
- Simulation results indicate significant improvements in latency and throughput compared to existing systems.
- RPU's design is crucial for future AI applications requiring high memory bandwidth.
Computer Science > Hardware Architecture arXiv:2602.18568 (cs) [Submitted on 20 Feb 2026] Title:RPU -- A Reasoning Processing Unit Authors:Matthew Adiletta, Gu-Yeon Wei, David Brooks View a PDF of the paper titled RPU -- A Reasoning Processing Unit, by Matthew Adiletta and 2 other authors View PDF HTML (experimental) Abstract:Large language model (LLM) inference performance is increasingly bottlenecked by the memory wall. While GPUs continue to scale raw compute throughput, they struggle to deliver scalable performance for memory bandwidth bound workloads. This challenge is amplified by emerging reasoning LLM applications, where long output sequences, low arithmetic intensity, and tight latency constraints demand significantly higher memory bandwidth. As a result, system utilization drops and energy per inference rises, highlighting the need for an optimized system architecture for scalable memory bandwidth. To address these challenges we present the Reasoning Processing Unit (RPU), a chiplet-based architecture designed to address the challenges of the modern memory wall. RPU introduces: (1) A Capacity-Optimized High-Bandwidth Memory (HBM-CO) that trades capacity for lower energy and cost; (2) a scalable chiplet architecture featuring a bandwidth-first power and area provisioning design; and (3) a decoupled microarchitecture that separates memory, compute, and communication pipelines to sustain high bandwidth utilization. Simulation results show that RPU performs up to 45....
