DeepStack: Scalable and Accurate Design Space Exploration for Distributed 3D-Stacked AI Accelerators

Fuente: arXiv
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Autori principali: Mo, Zhiwen, Li, Guoyu, Chen, Hao Mark, Cheng, Yu, Tang, Zhengju, Wang, Qianzhou, Wang, Lei, Liang, Shuang, Ma, Lingxiao, Zhou, Xianqi, Guo, Yuxiao, Luk, Wayne, Xue, Jilong, Fan, Hongxiang
Natura: Preprint
Pubblicazione: 2026
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author Mo, Zhiwen
Li, Guoyu
Chen, Hao Mark
Cheng, Yu
Tang, Zhengju
Wang, Qianzhou
Wang, Lei
Liang, Shuang
Ma, Lingxiao
Zhou, Xianqi
Guo, Yuxiao
Luk, Wayne
Xue, Jilong
Fan, Hongxiang
author_facet Mo, Zhiwen
Li, Guoyu
Chen, Hao Mark
Cheng, Yu
Tang, Zhengju
Wang, Qianzhou
Wang, Lei
Liang, Shuang
Ma, Lingxiao
Zhou, Xianqi
Guo, Yuxiao
Luk, Wayne
Xue, Jilong
Fan, Hongxiang
contents Advances in hybrid bonding and packaging have driven growing interest in 3D DRAM-stacked accelerators with higher memory bandwidth and capacity. As LLMs scale to hundreds of billions or trillions of parameters, distributed inference across multiple 3D chips becomes essential. With cross-stack co-design increasingly critical, we propose DeepStack, an accurate and efficient performance model and tool to enable early-stage system-hardware co-design space exploration (DSE) for distributed 3D-stacked AI systems. At the hardware level, DeepStack captures fine-grained 3D memory semantics such as transaction-aware bandwidth, bank activation constraints, buffering limitations, and thermal-power modeling. At the system level, DeepStack incorporates comprehensive parallelization strategies and execution scheduling for distributed LLM inference. With novel modeling techniques such as dual-stage network abstraction and tile-level compute-communication overlap, we achieve up to 100,000x faster runtime over state-of-the-art simulators at comparable accuracy, cross-validated against our in-house 3D designs, NS-3 backend (2.12%), and vLLM serving on 8xB200 GPUs (12.18%). With hierarchical design space search, DeepStack enables efficient exploration over 2.5x10^14 design points spanning 3D-stacked DRAM layers, DRAM vertical connectivity, interconnect, compute-memory allocation, and distributed scheduling. Compared with baseline designs, DeepStack achieves up to 9.5x higher throughput through co-optimized parallelism and 3D architecture search. Our DSE further reveals that batch size drives a more fundamental architectural divide than the prefill/decode distinction, and that parallelism strategy and hardware architecture are tightly coupled -- incomplete schedule search leads to permanently suboptimal silicon irrecoverable by software tuning. We intend to open source DeepStack to support future research.
format Preprint
id arxiv_https___arxiv_org_abs_2604_04750
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle DeepStack: Scalable and Accurate Design Space Exploration for Distributed 3D-Stacked AI Accelerators
Mo, Zhiwen
Li, Guoyu
Chen, Hao Mark
Cheng, Yu
Tang, Zhengju
Wang, Qianzhou
Wang, Lei
Liang, Shuang
Ma, Lingxiao
Zhou, Xianqi
Guo, Yuxiao
Luk, Wayne
Xue, Jilong
Fan, Hongxiang
Hardware Architecture
Distributed, Parallel, and Cluster Computing
Advances in hybrid bonding and packaging have driven growing interest in 3D DRAM-stacked accelerators with higher memory bandwidth and capacity. As LLMs scale to hundreds of billions or trillions of parameters, distributed inference across multiple 3D chips becomes essential. With cross-stack co-design increasingly critical, we propose DeepStack, an accurate and efficient performance model and tool to enable early-stage system-hardware co-design space exploration (DSE) for distributed 3D-stacked AI systems. At the hardware level, DeepStack captures fine-grained 3D memory semantics such as transaction-aware bandwidth, bank activation constraints, buffering limitations, and thermal-power modeling. At the system level, DeepStack incorporates comprehensive parallelization strategies and execution scheduling for distributed LLM inference. With novel modeling techniques such as dual-stage network abstraction and tile-level compute-communication overlap, we achieve up to 100,000x faster runtime over state-of-the-art simulators at comparable accuracy, cross-validated against our in-house 3D designs, NS-3 backend (2.12%), and vLLM serving on 8xB200 GPUs (12.18%). With hierarchical design space search, DeepStack enables efficient exploration over 2.5x10^14 design points spanning 3D-stacked DRAM layers, DRAM vertical connectivity, interconnect, compute-memory allocation, and distributed scheduling. Compared with baseline designs, DeepStack achieves up to 9.5x higher throughput through co-optimized parallelism and 3D architecture search. Our DSE further reveals that batch size drives a more fundamental architectural divide than the prefill/decode distinction, and that parallelism strategy and hardware architecture are tightly coupled -- incomplete schedule search leads to permanently suboptimal silicon irrecoverable by software tuning. We intend to open source DeepStack to support future research.
title DeepStack: Scalable and Accurate Design Space Exploration for Distributed 3D-Stacked AI Accelerators
topic Hardware Architecture
Distributed, Parallel, and Cluster Computing
url https://arxiv.org/abs/2604.04750