arXiv subjects

Windsor Hsu

Publications and source records attributed to Windsor Hsu.

2 recordsLinked to original sources

arXiv2026

PlanB: Efficient Software IPv6 Lookup with Linearized $B^+$-Tree

IP lookup via Longest Prefix Match (LPM) is critical for packet forwarding. Unfortunately, conventional lookup algorithms are inefficient for IPv6 Forwarding Information Bases (FIBs), which are characterized by a set of long prefixes with diverse lengths. We observe that LPM inherently represents a two-dimensional (2D) search problem over both prefix values and prefix lengths, but existing algorithms mostly treat LPM as two separate levels of one-dimensional (1D) searches, causing poor lookup performance and high memory overhead. This paper presents PlanB, a novel scheme for high-speed IPv6 lookup. We transform the 2D LPM into an equivalent 1D search problem over elementary intervals, thereby unifying the search across prefix value and lengths. We then adapt a flat-array-based B-tree structure to the needs of LPM to propose the linearized $B^+$-tree, based on which we introduce an efficient search algorithm tailored to the properties of the transformed space. To maximize performance, we integrate PlanB with vectorization, batching, branch-free logic, and loop unrolling to fully exploit CPU parallelism. Extensive evaluation shows that PlanB achieves single-core performance of 390 Million Lookups Per Sec (MLPS) with real-world IPv6 FIBs on AMD processor, and scales to full-12-core performance of 3.4 Billion Lookups Per Sec (BLPS). This is 1.6$\times$$\sim$14$\times$ higher than state-of-the-art software-based schemes (PopTrie, CP-Trie, Neurotrie and HBS).

cs.DS↗

arXiv2025

DFUSE: Strongly Consistent Write-Back Kernel Caching for Distributed Userspace File Systems

Cloud platforms host thousands of tenants that demand POSIX semantics, high throughput, and rapid evolution from their storage layer. Kernel-native distributed file systems supply raw speed, but their privileged code base couples every release to the kernel, widens the blast radius of crashes, and slows innovation. FUSE-based distributed file systems flip those trade-offs: they run in user space for fast deployment and strong fault isolation, yet the FUSE interface disables the kernel's write-back page cache whenever strong consistency is required. Practitioners must therefore choose between (i) weak consistency with fast write-back caching or (ii) strong consistency with slow write-through I/O, a limitation that has kept FUSE distributed file systems out of write-intensive cloud workloads. To this end, we present DFUSE, the first distributed FUSE file system that delivers write-back kernel caching and strong consistency. DFUSE achieves this by offloading userspace consistency control to the kernel driver, allowing coordinated access to the kernel's page cache across nodes. This design eliminates blind local cache updates and ensures cluster-wide strong consistency without compromising performance. In our evaluation, DFUSE achieves up to 68.0% higher throughput and 40.4% lower latency than the existing write-through design of FUSE-based distributed file systems.

cs.OS↗