Changmin Shin 0002

dblp:18/5384-2 · DBLP profile ↗
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5ranked-venue papers
2as first author
5since 2021 · last 2026
0009-0004-8242-8330ORCID · verified

Domains — the database's venue-derived domains; a paper can count in several

Systems, architecture and hardware · 5 · 2 first-author · 5 since 2021Software engineering, systems software and programming languages · 1 · 1 since 2021
YearPublicationVenuePosition
2026 A Cost-Effective Near-Storage Processing Solution for Offline Inference of Long-Context LLMs
abstract
The computational and memory demands of large language models for generative inference present significant challenges for practical deployment. One promising solution targeting offline inference is offloading-based batched inference, which extends the GPU's memory hierarchy with host memory and storage. However, it often suffers from substantial I/O overhead, primarily due to the large KV cache sizes that scale with batch size and context window length.
Hongsun Jang, Jaeyong Song 0002, Changmin Shin 0002, Si Ung Noh, Jaewon Jung 0001, Jisung Park 0001, Jinho Lee 0001
ASPLOS (2)3
2026 FlexiWalker: Extensible GPU Framework for Efficient Dynamic Random Walks with Runtime Adaptation
abstract
Dynamic random walks are fundamental to various graph analysis applications, offering advantages by adapting to evolving graph properties. Their runtime-dependent transition probabilities break down the pre-computation strategy that underpins most existing CPU and GPU static random walk optimizations. This leaves practitioners suffering from suboptimal frameworks and having to write hand-tuned kernels that do not adapt to workload diversity. To handle this issue, we present FlexiWalker, the first GPU framework that delivers efficient, workload-generic support for dynamic random walks. Our design-space study shows that rejection sampling and reservoir sampling are more suitable than other sampling techniques under massive parallelism. Thus, we devise (i) new high-performance kernels for them that eliminate global reductions, redundant memory accesses, and random-number generation. Given the necessity of choosing the best-fitting sampling strategy at runtime, we adopt (ii) a lightweight first-order cost model that selects the faster kernel per node at runtime. To enhance usability, we introduce (iii) a compile-time component that automatically specializes user-supplied walk logic into optimized building blocks. On various dynamic random walk workloads with real-world graphs, FlexiWalker outperforms the best published CPU/GPU baselines by geometric means of 73.44× and 5.91×, respectively, while successfully executing workloads that prior systems cannot support. We open-source FlexiWalker in https://github.com/AIS-SNU/FlexiWalker.
Seongyeon Park, Jaeyong Song 0002, Changmin Shin 0002, Sukjin Kim, Junguk Hong, Jinho Lee 0001
EuroSys3
2026 LoCaLUT: Harnessing Capacity-Computation Tradeoffs for LUT-Based Inference in DRAM-PIM
abstract
Lookup tables (LUTs) have recently gained attention as an alternative compute mechanism that maps input operands to precomputed results, eliminating the need for arithmetic logic. LUTs not only reduce logic complexity, but also naturally support diverse numerical precisions without requiring separate circuits for each bitwidth—an increasingly important feature in quantized DNNs. This creates a favorable tradeoff in PIM: memory capacity can be used in place of logic to increase computational throughput, aligning well with DRAM-PIM architectures that offer high bandwidth and easily available memory but limited logic density. In this work, we explore this capacity-computation tradeoff in LUT-based PIM designs, where memory capacity is traded for performance by packing multiple MAC operations into a single LUT lookup. Building on this insight, we propose LoCaLUT, a PIM-based design for efficient low-bit quantized DNN inference using operation-packed LUTs. First, we observe that these LUTs contain extensive redundancy and introduce LUT canonicalization, which eliminates duplicate entries to reduce LUT size. Second, we propose reordering LUT, a lightweight auxiliary LUT that remaps weight vectors to their canonical form required by LUT canonicalization with a simple LUT lookup. Third, we propose LUT slice streaming, a novel execution strategy that exploits the DRAM-buffer hierarchy by streaming only relevant LUT columns into the buffer and reusing them across multiple weight vectors. Evaluated on a real system based on UPMEM devices, we demonstrate a geometric mean speedup of$1.82 \times$across various numeric precisions and DNN models. We believe LoCaLUT opens a path toward scalable, low-logic PIM designs tailored for LUT-based DNN inference. Our implementation of LoCaLUT is available at https://github.com/AIS-SNU/LoCaLUT.
Junguk Hong, Changmin Shin 0002, Sukjin Kim, Si Ung Noh, Taehee Kwon 0002, Seongyeon Park, Hanjun Kim 0001, Youngsok Kim, Jinho Lee 0001
HPCA2
2025 Piccolo: Large-Scale Graph Processing with Fine-Grained in-Memory Scatter-Gather
abstract
Graph processing requires irregular, fine-grained random access patterns incompatible with contemporary off-chip memory architecture, leading to inefficient data access. This inefficiency makes graph processing an extremely memory-bound application. Because of this, existing graph processing accelerators typically employ a graph tiling-based or processing-in-memory (PIM) approach to relieve the memory bottleneck. In the tiling-based approach, a graph is split into chunks that fit within the on-chip cache to maximize data reuse. In the PIM approach, arithmetic units are placed within memory to perform operations such as reduction or atomic addition. However, both approaches have several limitations, especially when implemented on current memory standards (i.e., DDR). Because the access granularity provided by DDR is much larger than that of the graph vertex property data, much of the bandwidth and cache capacity are wasted. PIM is meant to alleviate such issues, but it is difficult to use in conjunction with the tiling-based approach, resulting in a significant disadvantage. Furthermore, placing arithmetic units inside a memory chip is expensive, thereby supporting multiple types of operation is thought to be impractical. To address the above limitations, we present Piccolo, an end-to-end efficient graph processing accelerator with fine-grained in-memory random scatter-gather. Instead of placing expensive arithmetic units in off-chip memory, Piccolo focuses on reducing the off-chip traffic with non-arithmetic function-in-memory of random scatter-gather. To fully benefit from in-memory scatter-gather, Piccolo redesigns the cache and miss-handling architecture (MHA) of the accelerator such that it can enjoy both the advantage of tiling and in-memory operations. Piccolo achieves a maximum speedup of 3.28 × and a geometric mean speedup of 1.62 ×, along with up to 59.7% reduction in energy consumption across various and extensive benchmarks.
Changmin Shin 0002, Jaeyong Song 0002, Hongsun Jang, Dogeun Kim, Jun Sung, Taehee Kwon 0002, Jae Hyung Ju, Frank Liu 0001, YeonKyu Choi, Jinho Lee 0001
HPCA1
2025 FALA: Locality-Aware PIM-Host Cooperation for Graph Processing with Fine-Grained Column Access
Changmin Shin 0002, Jaeyong Song 0002, Seongmin Na, Jun Sung, Hongsun Jang, Jinho Lee 0001
MICRO1