Pub Date : 2025-03-15DOI: 10.1109/LCA.2025.3570667
Sanjali Yadav;Bahar Asgari
Sparse matrix-matrix multiplication (SpGEMM) is a critical operation in numerous fields, including scientific computing, graph analytics, and deep learning, leveraging matrix sparsity to reduce both storage and computation costs. However, the irregular structure of sparse matrices poses significant challenges for performance optimization. Existing hardware accelerators often employ fixed dataflows designed for specific sparsity patterns, leading to performance degradation when the input deviates from these assumptions. As SpGEMM adoption expands across a broad spectrum of sparsity workloads, the demand grows for accelerators capable of dynamically adapting their dataflow schemes to diverse sparsity patterns. To address this, we propose DynaFlow, a machine learning-based framework that trains on the set of dataflows supported by any given accelerator and learns to predict the optimal dataflow based on the input sparsity pattern. By leveraging decision trees and deep reinforcement learning, DynaFlow surpasses static dataflow selection approaches, achieving up to a 50× speedup.
{"title":"DynaFlow: An ML Framework for Dynamic Dataflow Selection in SpGEMM Accelerators","authors":"Sanjali Yadav;Bahar Asgari","doi":"10.1109/LCA.2025.3570667","DOIUrl":"https://doi.org/10.1109/LCA.2025.3570667","url":null,"abstract":"Sparse matrix-matrix multiplication (SpGEMM) is a critical operation in numerous fields, including scientific computing, graph analytics, and deep learning, leveraging matrix sparsity to reduce both storage and computation costs. However, the irregular structure of sparse matrices poses significant challenges for performance optimization. Existing hardware accelerators often employ fixed dataflows designed for specific sparsity patterns, leading to performance degradation when the input deviates from these assumptions. As SpGEMM adoption expands across a broad spectrum of sparsity workloads, the demand grows for accelerators capable of dynamically adapting their dataflow schemes to diverse sparsity patterns. To address this, we propose DynaFlow, a machine learning-based framework that trains on the set of dataflows supported by any given accelerator and learns to predict the optimal dataflow based on the input sparsity pattern. By leveraging decision trees and deep reinforcement learning, DynaFlow surpasses static dataflow selection approaches, achieving up to a 50× speedup.","PeriodicalId":51248,"journal":{"name":"IEEE Computer Architecture Letters","volume":"24 1","pages":"189-192"},"PeriodicalIF":1.4,"publicationDate":"2025-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144205869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Retrieval-Augmented Generation (RAG) is crucial for improving the quality of large language models by injecting proper contexts extracted from external sources. RAG requires high-throughput, low-latency Approximate Nearest Neighbor Search (ANNS) over billion-scale vector databases. Conventional DRAM/SSD solutions face capacity/latency limits, whereas specialized hardware or RDMA clusters lack flexibility or incur network overhead. We present Cosmos, integrating general-purpose cores within CXL memory devices for full ANNS offload and introducing rank-level parallel distance computation to maximize memory bandwidth. We also propose an adjacency-aware data placement that balances search loads across CXL devices based on inter-cluster proximity. Evaluations on SIFT1B and DEEP1B traces show that Cosmos achieves up to 6.72× higher throughput than the baseline CXL system and 2.35× over a state-of-the-art CXL-based solution, demonstrating scalability for RAG pipelines.
{"title":"Cosmos: A CXL-Based Full In-Memory System for Approximate Nearest Neighbor Search","authors":"Seoyoung Ko;Hyunjeong Shim;Wanju Doh;Sungmin Yun;Jinin So;Yongsuk Kwon;Sang-Soo Park;Si-Dong Roh;Minyong Yoon;Taeksang Song;Jung Ho Ahn","doi":"10.1109/LCA.2025.3570235","DOIUrl":"https://doi.org/10.1109/LCA.2025.3570235","url":null,"abstract":"Retrieval-Augmented Generation (RAG) is crucial for improving the quality of large language models by injecting proper contexts extracted from external sources. RAG requires high-throughput, low-latency Approximate Nearest Neighbor Search (ANNS) over billion-scale vector databases. Conventional DRAM/SSD solutions face capacity/latency limits, whereas specialized hardware or RDMA clusters lack flexibility or incur network overhead. We present <sc>Cosmos</small>, integrating general-purpose cores within CXL memory devices for full ANNS offload and introducing rank-level parallel distance computation to maximize memory bandwidth. We also propose an adjacency-aware data placement that balances search loads across CXL devices based on inter-cluster proximity. Evaluations on SIFT1B and DEEP1B traces show that <sc>Cosmos</small> achieves up to 6.72× higher throughput than the baseline CXL system and 2.35× over a state-of-the-art CXL-based solution, demonstrating scalability for RAG pipelines.","PeriodicalId":51248,"journal":{"name":"IEEE Computer Architecture Letters","volume":"24 1","pages":"173-176"},"PeriodicalIF":1.4,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144196731","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
As computer systems become more complex, evaluating performance requires tracking various hardware performance counters that capture the system’s internal activities. While these counters provide valuable insights, their growing number makes it challenging to identify the most relevant ones for performance analysis. In this paper, we investigate the correlation between performance counter values and overall system performance, while also exploring the inter-correlation between different counters. Our findings demonstrate that specific counters are strongly correlated with key performance metrics and that significant redundancy exists among counters. By leveraging these relationships, we propose a method for selecting a small, representative set of performance counters. This streamlined set can further be used to accurately predict performance score across various workloads and system configurations.
{"title":"Minimal Counters, Maximum Insight: Simplifying System Performance With HPC Clusters for Optimized Monitoring","authors":"Shubhi Shukla;Abhijeet Singh;Rajdeep Chakraborty;Anirban Chakraborty;Tejas Rathod;Harshal Mumbaikar;Manoj Kumar Munigala;Madhusudhan K N;Pabitra Mitra;Debdeep Mukhopadhyay","doi":"10.1109/LCA.2025.3570157","DOIUrl":"https://doi.org/10.1109/LCA.2025.3570157","url":null,"abstract":"As computer systems become more complex, evaluating performance requires tracking various hardware performance counters that capture the system’s internal activities. While these counters provide valuable insights, their growing number makes it challenging to identify the most relevant ones for performance analysis. In this paper, we investigate the correlation between performance counter values and overall system performance, while also exploring the inter-correlation between different counters. Our findings demonstrate that specific counters are strongly correlated with key performance metrics and that significant redundancy exists among counters. By leveraging these relationships, we propose a method for selecting a small, representative set of performance counters. This streamlined set can further be used to accurately predict performance score across various workloads and system configurations.","PeriodicalId":51248,"journal":{"name":"IEEE Computer Architecture Letters","volume":"24 1","pages":"177-180"},"PeriodicalIF":1.4,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144196730","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-11DOI: 10.1109/LCA.2025.3549423
Amin Mamandipoor;Huy Dinh Tran;Mohammad Alian
Networking is considered a datacenter tax, and hyperscalers push hard to provide high-performance networking with minimal resource expenditure. To keep up with the ever-increasing network rates, many CPU cycles are spent on the networking tax. We make a key observation that network processing threads can be simultaneously executed on server CPUs with minimal interference with the application threads. However, utilizing simultaneous multithreading (SMT) to scale the number of network threads with the number of application threads suffers from (1) failing to provide strict tail latency requirements for latency-critical applications, and (2) reducing the number of available hardware threads for application processes, thus contributing to a high datacenter network tax. In this work, we design, implement, and evaluate a chip-multiprocessor (CMP) with specialized Simultaneous Data-delivery Threads (SDT) per physical core. The key insight is that with judicious partitioning at the architectural level, SDT can safely co-run with application processes with guaranteed performance isolation. Our evaluation results, using full-system simulation, show that a 20-core CMP enhanced with SDT reduces the area and power consumption of a baseline 40-core CMP by 47.5% and 66%, respectively, while reducing network throughput by less than 10%.
{"title":"SDT: Cutting Datacenter Tax Through Simultaneous Data-Delivery Threads","authors":"Amin Mamandipoor;Huy Dinh Tran;Mohammad Alian","doi":"10.1109/LCA.2025.3549423","DOIUrl":"https://doi.org/10.1109/LCA.2025.3549423","url":null,"abstract":"Networking is considered a datacenter tax, and hyperscalers push hard to provide high-performance networking with minimal resource expenditure. To keep up with the ever-increasing network rates, many CPU cycles are spent on the networking tax. We make a key observation that network processing threads can be simultaneously executed on server CPUs with minimal interference with the application threads. However, utilizing simultaneous multithreading (SMT) to scale the number of network threads with the number of application threads suffers from (1) failing to provide strict tail latency requirements for latency-critical applications, and (2) reducing the number of available hardware threads for application processes, thus contributing to a high datacenter network tax. In this work, we design, implement, and evaluate a chip-multiprocessor (CMP) with specialized Simultaneous Data-delivery Threads (SDT) per physical core. The key insight is that with judicious partitioning at the architectural level, SDT can safely co-run with application processes with guaranteed performance isolation. Our evaluation results, using full-system simulation, show that a 20-core CMP enhanced with SDT reduces the area and power consumption of a baseline 40-core CMP by 47.5% and 66%, respectively, while reducing network throughput by less than 10%.","PeriodicalId":51248,"journal":{"name":"IEEE Computer Architecture Letters","volume":"24 1","pages":"93-96"},"PeriodicalIF":1.4,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143777969","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-07DOI: 10.1109/LCA.2025.3567844
Minseok Seo;Jungi Hyun;Seongho Jeong;Xuan Truong Nguyen;Hyuk-Jae Lee;Hyokeun Lee
The key-value (KV) cache in large language models (LLMs) now necessitates a substantial amount of memory capacity as its size proportionally grows with the context’s size. Recently, Compute-Express Link (CXL) memory becomes a promising method to secure memory capacity. However, CXL memory in a GPU-based LLM inference platform entails performance and scalability challenges due to the limited bandwidth of CXL memory. This paper proposes OASIS, an outlier-aware KV cache clustering for scaling LLM inference in CXL memory systems. Our method is based on the observation that clustering is effective in trading off between performance and accuracy compared to previous quantization- or selection-based approaches if clustering is aware of outliers. Our evaluation shows OASIS yields 3.6× speedup compared to the case without clustering while preserving accuracy with just 5% of full KV cache.
{"title":"OASIS: Outlier-Aware KV Cache Clustering for Scaling LLM Inference in CXL Memory Systems","authors":"Minseok Seo;Jungi Hyun;Seongho Jeong;Xuan Truong Nguyen;Hyuk-Jae Lee;Hyokeun Lee","doi":"10.1109/LCA.2025.3567844","DOIUrl":"https://doi.org/10.1109/LCA.2025.3567844","url":null,"abstract":"The key-value (KV) cache in large language models (LLMs) now necessitates a substantial amount of memory capacity as its size proportionally grows with the context’s size. Recently, Compute-Express Link (CXL) memory becomes a promising method to secure memory capacity. However, CXL memory in a GPU-based LLM inference platform entails performance and scalability challenges due to the limited bandwidth of CXL memory. This paper proposes OASIS, an outlier-aware KV cache clustering for scaling LLM inference in CXL memory systems. Our method is based on the observation that clustering is effective in trading off between performance and accuracy compared to previous quantization- or selection-based approaches if clustering is aware of outliers. Our evaluation shows OASIS yields 3.6× speedup compared to the case without clustering while preserving accuracy with just 5% of full KV cache.","PeriodicalId":51248,"journal":{"name":"IEEE Computer Architecture Letters","volume":"24 1","pages":"165-168"},"PeriodicalIF":1.4,"publicationDate":"2025-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144139974","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
High-performance computing applications rely heavily on vector instructions to accelerate data processing. In this letter, we propose a controllable bitonic network (CBN) and use it as a lane interconnect to efficiently rearrange data across vector lanes of a vector processing unit to accelerate the execution of vector permutation instructions (VPIs). Our work focuses on the RISC-V vector instruction set because of its configurable vector length support. Through simulations with vector-permutation-intensive applications of a RISC-V vector benchmark suite (RiVEC), the proposed approach with an eight-lane 64-bit CBN demonstrates an average speedup of ≥6× regarding the VPI execution time over a conventional ring-network-based approach. In addition, to verify our approach on hardware, we implemented a processor system with an eight-lane 16-bit CBN on an AMD A7-100T FPGA operating at 20 MHz, demonstrating single-cycle execution of the RISC-V vr.gather and vr.scatter instructions.
{"title":"Accelerating Vector Permutation Instruction Execution via Controllable Bitonic Network","authors":"Shabirahmed Badashasab Jigalur;Daniel Jiménez Mazure;Teresa Cervero Garcia;Yen-Cheng Kuan","doi":"10.1109/LCA.2025.3548527","DOIUrl":"https://doi.org/10.1109/LCA.2025.3548527","url":null,"abstract":"High-performance computing applications rely heavily on vector instructions to accelerate data processing. In this letter, we propose a controllable bitonic network (CBN) and use it as a lane interconnect to efficiently rearrange data across vector lanes of a vector processing unit to accelerate the execution of vector permutation instructions (VPIs). Our work focuses on the RISC-V vector instruction set because of its configurable vector length support. Through simulations with vector-permutation-intensive applications of a RISC-V vector benchmark suite (RiVEC), the proposed approach with an eight-lane 64-bit CBN demonstrates an average speedup of ≥6× regarding the VPI execution time over a conventional ring-network-based approach. In addition, to verify our approach on hardware, we implemented a processor system with an eight-lane 16-bit CBN on an AMD A7-100T FPGA operating at 20 MHz, demonstrating single-cycle execution of the RISC-V <italic>vr.gather</i> and <italic>vr.scatter</i> instructions.","PeriodicalId":51248,"journal":{"name":"IEEE Computer Architecture Letters","volume":"24 1","pages":"133-136"},"PeriodicalIF":1.4,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143913300","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The lookup table (LUT)-based Processing-in-Memory (PIM) solutions perform computations by looking up precomputed results stored in LUTs, providing exceptional efficiency for complex operations such as multiplication, making them highly suitable for energy- and latency-efficient Convolutional Neural Network (CNN) inference tasks. However, including all possible results in the LUT naively demands exponential hardware resources, significantly limiting parallelism and increasing hardware area, latency, and power overhead. While decomposition and compression techniques can reduce the LUT size, they also introduce considerable memory access overhead and additional operations. To address these challenges, we conduct an extensive analysis to identify which data portions significantly impact accuracy in CNNs. Based on the insight that key data is concentrated in a small range, we propose a data-pattern-driven (DPD) optimization strategy, which approximates less critical data to drastically reduce LUT size while preserving computational efficiency with acceptable accuracy loss.
{"title":"Data-Pattern-Driven LUT for Efficient In-Cache Computing in CNNs Acceleration","authors":"Zhengpan Fei;Mingchuan Lyu;Satoshi Kawakami;Koji Inoue","doi":"10.1109/LCA.2025.3548080","DOIUrl":"https://doi.org/10.1109/LCA.2025.3548080","url":null,"abstract":"The lookup table (LUT)-based Processing-in-Memory (PIM) solutions perform computations by looking up precomputed results stored in LUTs, providing exceptional efficiency for complex operations such as multiplication, making them highly suitable for energy- and latency-efficient Convolutional Neural Network (CNN) inference tasks. However, including all possible results in the LUT naively demands exponential hardware resources, significantly limiting parallelism and increasing hardware area, latency, and power overhead. While decomposition and compression techniques can reduce the LUT size, they also introduce considerable memory access overhead and additional operations. To address these challenges, we conduct an extensive analysis to identify which data portions significantly impact accuracy in CNNs. Based on the insight that key data is concentrated in a small range, we propose a data-pattern-driven (DPD) optimization strategy, which approximates less critical data to drastically reduce LUT size while preserving computational efficiency with acceptable accuracy loss.","PeriodicalId":51248,"journal":{"name":"IEEE Computer Architecture Letters","volume":"24 1","pages":"81-84"},"PeriodicalIF":1.4,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143706788","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Differential privacy (DP) and federated learning (FL) have emerged as important privacy-preserving approaches when using sensitive data to train machine learning models. FL ensures that raw sensitive data does not leave the users’ devices by training the model in a distributed manner. DP ensures that the model does not leak any information about an individual by clipping and adding noise to the gradients. However, real-life deployments of such algorithms assume that the third-party application implementing DP-based FL is trusted, and is thus given access to sensitive data on the data owner’s device/server. In this work, we propose DPWatch, a hardware-based framework for ML accelerators that enforces guarantees that a third party application cannot leak sensitive user data used for training and ensures that the gradients are appropriately noised before leaving the device. We evaluate DPWatch on two accelerators and demonstrate small area and performance overheads.
{"title":"DPWatch: A Framework for Hardware-Based Differential Privacy Guarantees","authors":"Pawan Kumar Sanjaya;Christina Giannoula;Ian Colbert;Ihab Amer;Mehdi Saeedi;Gabor Sines;Nandita Vijaykumar","doi":"10.1109/LCA.2025.3547262","DOIUrl":"https://doi.org/10.1109/LCA.2025.3547262","url":null,"abstract":"Differential privacy (DP) and federated learning (FL) have emerged as important privacy-preserving approaches when using sensitive data to train machine learning models. FL ensures that raw sensitive data does not leave the users’ devices by training the model in a distributed manner. DP ensures that the model does not leak any information about an individual by <italic>clipping</i> and adding <italic>noise</i> to the gradients. However, real-life deployments of such algorithms assume that the third-party application implementing DP-based FL is trusted, and is thus given access to sensitive data on the data owner’s device/server. In this work, we propose DPWatch, a hardware-based framework for ML accelerators that enforces guarantees that a third party application cannot leak sensitive user data used for training and ensures that the gradients are appropriately noised before leaving the device. We evaluate DPWatch on two accelerators and demonstrate small area and performance overheads.","PeriodicalId":51248,"journal":{"name":"IEEE Computer Architecture Letters","volume":"24 1","pages":"89-92"},"PeriodicalIF":1.4,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143761420","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-02DOI: 10.1109/LCA.2025.3566553
Mattia Tibaldi;Christian Pilato
To reduce emerging carbon emissions in cloud computing, we proposed Amethyst, a new VM placement and migration strategy capable of adapting consumption to the currently available green energy. Amethyst tackles the problem on three fronts: it adjusts the consumption to energy production, optimizes execution on FPGA accelerators, and balances execution among servers. We evaluate the strategy with real workloads. Our simulations on CloudSim Plus show that Amethyst effectively reduces the carbon emissions of cloud computing and, compared to the state-of-the-art, it increases the energy efficiency.
{"title":"Amethyst: Reducing Data Center Emissions With Dynamic Autotuning and VM Management","authors":"Mattia Tibaldi;Christian Pilato","doi":"10.1109/LCA.2025.3566553","DOIUrl":"https://doi.org/10.1109/LCA.2025.3566553","url":null,"abstract":"To reduce emerging carbon emissions in cloud computing, we proposed Amethyst, a new VM placement and migration strategy capable of adapting consumption to the currently available green energy. Amethyst tackles the problem on three fronts: it adjusts the consumption to energy production, optimizes execution on FPGA accelerators, and balances execution among servers. We evaluate the strategy with real workloads. Our simulations on CloudSim Plus show that Amethyst effectively reduces the carbon emissions of cloud computing and, compared to the state-of-the-art, it increases the energy efficiency.","PeriodicalId":51248,"journal":{"name":"IEEE Computer Architecture Letters","volume":"24 1","pages":"153-156"},"PeriodicalIF":1.4,"publicationDate":"2025-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144139909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-02DOI: 10.1109/LCA.2025.3566692
Kyoungho Jeun;Hyeonu Kim;Eojin Lee
The increasing demand for on-device AI applications has shifted focus to Small Language Models (SLMs) optimized for mobile environments. However, the limited memory bandwidth of LPDDR5-based systems presents significant challenges for efficiently executing memory-bound matrix-vector multiplication operations, a core component of SLM inference. In this paper, we propose Fold-PIM, an LPDDR5-based Processing-in-Memory (PIM) architecture designed to address these challenges. Fold-PIM features a shared PU architecture that leverages subarray-level parallelism and employs key techniques with in-tile transposition, adaptive tiling, and a tailored protocol to reduce vector replacement latency. Our evaluation results demonstrate that Fold-PIM achieves up to 3.9× speedup of token generation time in SLM inference compared to the baseline system without PIM.
{"title":"Fold-PIM: A Cost-Efficient LPDDR5-Based PIM for On-Device SLMs","authors":"Kyoungho Jeun;Hyeonu Kim;Eojin Lee","doi":"10.1109/LCA.2025.3566692","DOIUrl":"https://doi.org/10.1109/LCA.2025.3566692","url":null,"abstract":"The increasing demand for on-device AI applications has shifted focus to Small Language Models (SLMs) optimized for mobile environments. However, the limited memory bandwidth of LPDDR5-based systems presents significant challenges for efficiently executing memory-bound matrix-vector multiplication operations, a core component of SLM inference. In this paper, we propose Fold-PIM, an LPDDR5-based Processing-in-Memory (PIM) architecture designed to address these challenges. Fold-PIM features a shared PU architecture that leverages subarray-level parallelism and employs key techniques with in-tile transposition, adaptive tiling, and a tailored protocol to reduce vector replacement latency. Our evaluation results demonstrate that Fold-PIM achieves up to 3.9× speedup of token generation time in SLM inference compared to the baseline system without PIM.","PeriodicalId":51248,"journal":{"name":"IEEE Computer Architecture Letters","volume":"24 1","pages":"185-188"},"PeriodicalIF":1.4,"publicationDate":"2025-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144206124","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}