UMDAM: A Unified Data Layout and DRAM Address Mapping for Heterogenous NPU-PIM

Fuente: arXiv
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Main Author: Huang, Hai
Format: Preprint
Published: 2025
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author Huang, Hai
author_facet Huang, Hai
contents Large Language Models (LLMs) are increasingly deployed on edge devices with Neural Processing Units (NPUs), yet the decode phase remains memory-intensive, limiting performance. Processing-in-Memory (PIM) offers a promising solution, but co-executing NPU-PIM systems face challenges such as data layout mismatches, bandwidth loss, and redundant storage. To address these issues, we propose UMDAM, a unified memory-affinity data layout and DRAM address mapping scheme tailored for NPU-PIM co-execution. UMDAM employs a column-major, tile-based layout and a configurable DRAM mapping strategy to ensure compatibility with NPU computation while maximizing PIM efficiency -- without introducing extra memory overhead or bandwidth loss. Comprehensive evaluations on OPT models demonstrate that UMDAM reduces time-to-first-token (TTFT) by up to 3.0x and time-to-last-token (TTLT) by 2.18x, significantly improving end-to-end LLM inference efficiency on edge devices.
format Preprint
id arxiv_https___arxiv_org_abs_2511_03293
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle UMDAM: A Unified Data Layout and DRAM Address Mapping for Heterogenous NPU-PIM
Huang, Hai
Distributed, Parallel, and Cluster Computing
Large Language Models (LLMs) are increasingly deployed on edge devices with Neural Processing Units (NPUs), yet the decode phase remains memory-intensive, limiting performance. Processing-in-Memory (PIM) offers a promising solution, but co-executing NPU-PIM systems face challenges such as data layout mismatches, bandwidth loss, and redundant storage. To address these issues, we propose UMDAM, a unified memory-affinity data layout and DRAM address mapping scheme tailored for NPU-PIM co-execution. UMDAM employs a column-major, tile-based layout and a configurable DRAM mapping strategy to ensure compatibility with NPU computation while maximizing PIM efficiency -- without introducing extra memory overhead or bandwidth loss. Comprehensive evaluations on OPT models demonstrate that UMDAM reduces time-to-first-token (TTFT) by up to 3.0x and time-to-last-token (TTLT) by 2.18x, significantly improving end-to-end LLM inference efficiency on edge devices.
title UMDAM: A Unified Data Layout and DRAM Address Mapping for Heterogenous NPU-PIM
topic Distributed, Parallel, and Cluster Computing
url https://arxiv.org/abs/2511.03293