Graph Random Walks (GRWs) offer efficient approximations of key graph properties and have been widely adopted in many applications. However, GRW workloads are notoriously difficult to accelerate due to their strong data dependencies, irregular memory access patterns, and imbalanced execution behavior. While recent work explores FPGA-based accelerators for GRWs, existing solutions fall far short of hardware potential due to inefficient pipelining and static scheduling. This paper presents RidgeWalker, a high-performance GRW accelerator designed for datacenter FPGAs. The key insight behind RidgeWalker is that the Markov property of GRWs allows decomposition into stateless, fine-grained tasks that can be executed out-of-order without compromising correctness. Building on this insight, RidgeWalker introduces an asynchronous pipeline architecture with a feedback-driven scheduler grounded in queuing theory. This design enables perfect pipelining and adaptive load balancing. We prototype RidgeWalker on FPGAs and evaluate its performance across a range of GRW algorithms and real-world graph datasets. Experimental results demonstrate that RidgeWalker achieves an average speedup of 7.0× over state-of-the-art FPGA solutions and 8.1× over GPU solutions, with peak speedups of up to 71.0× and 22.9×, respectively. The source code is publicly available at https://github.com/Xtra-Computing/RidgeWalker.

Efficient graph processing is critical in various modern applications, such as social network analysis, recommendation systems, and large-scale data mining. Traditional single-FPGA systems struggle to handle the increasing size and complexity of real-world graphs due to limitations in memory and computational resources. Existing multi-FPGA solutions face significant challenges, including high communication overhead caused by irregular data transfer patterns and workload imbalances stemming from skewed graph distributions. These inefficiencies hinder scalability and performance, highlighting a critical research gap. To address these issues, we introduce Clementi, an efficient multi-FPGA graph processing framework that features customized fine-grained pipelines for computation and cross-FPGA communication. Clementi uniquely integrates an accurate performance model for execution time prediction, enabling a novel scheduling method that balances workload distribution and minimizes communication overhead by overlapping communication and computation stages. Experimental results demonstrate that Clementi achieves speedups of up to 8.75× compared to state-of-the-art multi-FPGA designs, indicating significant improvements in processing efficiency as the number of FPGAs increases. This near-linear scalability underscores the framework' s potential to enhance graph processing capabilities in practical applications. Clementi is open-sourced at https://github.com/Xtra-Computing/Clementi.

Leveraging GPUs' high parallelism can significantly improve the real-time computation efficiency of streaming graph processing. However, when a large-scale graph exceeds GPU memory capacity, CPU-GPU cooperative processing often results in substantial and irregular CPU-to-GPU data transfer overhead. This stems from the extensive redundant graph accesses during continuous computation, which can hardly be addressed by existing solutions. In this work, we present Grapin, an out-of-memory GPU streaming graph processing system designed to minimize graph data transfer via two effective techniques for eliminating redundant accesses: (1) Extending advanced incremental processing algorithms to GPUs by converting their heavyweight data dependency processing into GPU-friendly forms, eliminating redundant graph accesses from the computation side; and (2) providing a lightweight yet efficient GPU hot subgraph management framework that finely caches the frequently accessed dynamic subgraphs in a vertex-centric manner. Experimental results demonstrate that Grapin can efficiently process large-scale streaming graphs with billions of edges on a single NVIDIA A5000 GPU. Enabling incremental computation reduces data transfer by 61%, and the integration of GPU hot subgraph reuse further reduces the remaining transfer by 72%, resulting in a total reduction of 89%. Compared with CPU-based solutions, Grapin achieves speedups ranging from 1.8x to 96.9x (17.9x on average).

Graph dynamic random walks (GDRWs) have recently emerged as a powerful paradigm for graph analytics and learning applications, including graph embedding and graph neural networks. Despite the fact that many existing studies optimize the performance of GDRWs on multi-core CPUs, massive random memory accesses and costly synchronizations cause severe resource underutilization, and the processing of GDRWs is usually the key performance bottleneck in many graph applications. This paper studies an alternative architecture, FPGA, to address these issues in GDRWs, as FPGA has the ability of hardware customization so that we are able to explore fine-grained pipeline execution and specialized memory access optimizations. Specifically, we propose LightRW, a novel FPGA-based accelerator for GDRWs. LightRW embraces a series of optimizations to enable fine-grained pipeline execution on the chip and to exploit the massive parallelism of FPGA while significantly reducing memory accesses. As current commonly used sampling methods in GDRWs do not efficiently support fine-grained pipeline execution, we develop a parallelized reservoir sampling method to sample multiple vertices per cycle for efficient pipeline execution. To address the random memory access issues, we propose a degree-aware configurable caching method that buffers hot vertices on-chip to alleviate random memory accesses and a dynamic burst access engine that efficiently retrieves neighbors. Experimental results show that our optimization techniques are able to improve the performance of GDRWs on FPGA significantly. Moreover, LightRW delivers up to 9.55x and 9.10x speedup over the state-of-the-art CPU-based MetaPath and Node2vec random walks, respectively. This work is open-sourced on GitHub at https://github.com/Xtra-Computing/LightRW.

The use of FPGAs for efficient graph processing has attracted significant interest. Recent memory subsystem upgrades including the introduction of HBM in FPGAs promise to further alleviate memory bottlenecks. However, modern multi-channel HBM requires much more processing pipelines to fully utilize its bandwidth potential. Due to insufficient resource efficiency, existing designs do not scale well, resulting in underutilization of the HBM facilities even when all other resources are fully consumed. In this paper, we propose ReGraph1, which customizes heterogeneous pipelines for diverse workloads in graph processing, achieving better resource efficiency, instantiating more pipelines and improving performance. We first identify workload diversity exists in processing graph partitions and classify them into two types: dense partitions established with good locality and sparse partitions with poor locality. Subsequently, we design two types of pipelines: Little pipelines with burst memory access technique to process dense partitions and Big pipelines tolerating random memory access latency to handle sparse partitions. Unlike existing monolithic pipeline designs, our heterogeneous pipelines are tailored for more specific workload characteristics and hence more lightweight, allowing the architecture to scale up more effectively with limited resources. We also present a graph-aware task scheduling method that schedules partitions to the right pipeline types, generates the most efficient pipeline combination and balances workloads. ReGraph surpasses state-of-the-art FPGA accelerators by 1.6×–5.9× in performance and 2.5×–12.3× in resource efficiency.

FPGA has been an emerging computing infrastructure in datacenters benefiting from fine-grained parallelism, energy efficiency, and reconfigurability. Meanwhile, graph processing has attracted tremendous interest in data analytics, and its performance is in increasing demand with the rapid growth of data. Many works have been proposed to tackle the challenges of designing efficient FPGA-based accelerators for graph processing. However, the largely overlooked programmability still requires hardware design expertise and sizable development efforts from developers. ThunderGP , a high-level synthesis based graph processing framework on FPGAs, is hence proposed to close the gap, with which developers could enjoy high performance of FPGA-accelerated graph processing by writing only a few high-level functions with no knowledge of the hardware. ThunderGP adopts the gather-apply-scatter model as the abstraction of various graph algorithms and realizes the model by a built-in highly parallel and memory-efficient accelerator template. With high-level functions as inputs, ThunderGP automatically explores massive resources of multiple super-logic regions of modern FPGA platforms to generate and deploy accelerators, as well as schedule tasks for them. Although ThunderGP on DRAM-based platforms is memory bandwidth bounded, recent high bandwidth memory (HBM) brings large potentials to performance. However, the system bottleneck shifts from memory bandwidth to resource consumption on HBM-enabled platforms. Therefore, we further propose to improve resource efficiency of ThunderGP to utilize more memory bandwidth from HBM. We conduct evaluation with seven common graph applications and 19 graphs. ThunderGP on DRAM-based hardware platforms provides 1.9× ∼ 5.2× improvement on bandwidth efficiency over the state of the art, whereas ThunderGP on HBM-based hardware platforms delivers up to 5.2× speedup over the state-of-the-art RTL-based approach. This work is open sourced on GitHub at https://github.com/Xtra-Computing/ThunderGP .

FPGAs have become emerging computing infrastructures for accelerating applications in datacenters. Meanwhile, high-level synthesis (HLS) tools have been proposed to ease the programming of FPGAs. Even with HLS, irregular data-intensive applications require explicit optimizations, among which multiple processing elements (PEs) with each owning a private BRAM-based buffer are usually adopted to process multiple data per cycle. Data routing, which dynamically dispatches multiple data to designated PEs, avoids data replication in buffers compared to statically assigning data to PEs, hence saving BRAM usage. However, the workload imbalance among PEs vastly diminishes performance when processing skew datasets. In this paper, we propose a skew-oblivious data routing architecture that allocates secondary PEs and schedules them to share the workload of the overloaded PEs at run-time. In addition, we integrate the proposed architecture into a framework called Ditto to minimize the development efforts for applications that require skew handling. We evaluate Ditto on five commonly used applications: histogram building, data partitioning, pagerank, heavy hitter detection and hyperloglog. The results demonstrate that the generated implementations are robust to skew datasets and outperform the state-of-the-art designs in both throughput and BRAM usage efficiency.

FPGA has been an emerging computing infrastructure in datacenters benefiting from features of fine-grained parallelism, energy efficiency, and reconfigurability. Meanwhile, graph processing has attracted tremendous interest in data analytics, and its performance is in increasing demand with the rapid growth of data. Many works have been proposed to tackle the challenges of designing efficient FPGA-based accelerators for graph processing. However, the largely overlooked programmability still requires hardware design expertise and sizable development efforts from developers.

In this paper, we propose ThundeRiNG, a resource-efficient and high-throughput system for generating multiple independent sequences of random numbers (MISRN) on FPGAs. Generating MISRN can be a time-consuming step in many applications such as numeric computation and approximate computing. Despite that decades of studies on generating a single sequence of random numbers on FPGAs have achieved very high throughput and high quality of randomness, existing MISRN approaches either suffer from heavy resource consumption or fail to achieve statistical independence among sequences. In contrast, ThundeRiNG resolves the dependence by using a resource-efficient decorrelator among multiple sequences, guaranteeing a high statistical quality of randomness. Moreover, ThundeRiNG develops a novel state sharing among a massive number of pseudo-random number generator instances on FPGAs. The experimental results show that ThundeRiNG successfully passes the widely used statistical test, TestU01, only consumes a constant number of DSPs (less than 1% of the FPGA resource capacity) for generating any number of sequences, and achieves a throughput of 655 billion random numbers per second. Compared to the state-of-the-art GPU library, ThundeRiNG demonstrates a 10.62x speedup on MISRN and delivers up to 9.15x performance and 26.63x power efficiency improvement on two applications (pi estimation and Monte Carlo option pricing). This work is open-sourced on Github at https://github.com/Xtra-Computing/ThundeRiNG.

The pervasive adoption of Deep Learning (DL) and Graph Processing (GP) makes it a de facto requirement to build large-scale clusters of heterogeneous accelerators including GPUs and FPGAs. The OpenCL programming framework can be used on the individual nodes of such clusters but is not intended for deployment in a distributed manner. Fortunately, the original OpenCL semantics naturally fit into the programming environment of heterogeneous clusters. In this paper, we propose a heterogeneity-aware OpenCL-like (HaoCL) programming framework to facilitate the programming of a wide range of scientific applications including DL and GP workloads on large-scale heterogeneous clusters. With HaoCL, existing applications can be directly deployed on heterogeneous clusters without any modifications to the original OpenCL source code and without awareness of the underlying hardware topologies and configurations. Our experiments show that HaoCL imposes a negligible overhead in a distributed environment, and provides near-liner speedups on standard benchmarks when computation or data size exceeds the capacity of a single node. The system design and the evaluations are presented in this demo paper.