A Dependency-Aware Multi-GPU Training Framework for Temporal Graph Neural Networks
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arXiv:2610.15730v1 [cs.LG] 11 Oct 2026
A Dependency-Aware Multi-GPU Training Framework for Temporal Graph Neural Networks Yang Zhao∗
Yue Dai∗
Liang Qiao
yang_zhao@mail.ustc.edu.cn University of Science and Technology of China Hefei, Anhui, China
ydai21@illinoistech.edu Illinois Institute of Technology Chicago, Illinois, USA
ql1an9@mail.ustc.edu.cn University of Science and Technology of China Hefei, Anhui, China
Buxin Tu
Bo Liu
Sen Zhang
tubuxin@mail.ustc.edu.cn University of Science and Technology of China Hefei, Anhui, China
liubo22@mail.ustc.edu.cn University of Science and Technology of China Hefei, Anhui, China
sen@mail.ustc.edu.cn University of Science and Technology of China Hefei, Anhui, China
Yi Zhang
Xiaoyu Hao
Jun Shi
yi_zhang@mail.ustc.edu.cn University of Science and Technology of China Hefei, Anhui, China
haoxiaoyu@mail.ustc.edu.cn University of Science and Technology of China Hefei, Anhui, China
shijun18@ustc.edu.cn University of Science and Technology of China Hefei, Anhui, China
Junshi Chen
Hong An
cjuns@ustc.edu.cn University of Science and Technology of China Hefei, Anhui, China
han@ustc.edu.cn University of Science and Technology of China Hefei, Anhui, China
Abstract
(3) critical-path optimization to prioritize urgent memory updates while deferring non-critical work during multi-GPU pipeline execution. Experimental results across representative models and diverse datasets show that DepBloom achieves an average speedup of 2.84× and up to 5.16× over state-of-the-art methods, while maintaining comparable or better model accuracy.
Temporal graph neural networks (TGNNs) achieve superior performance in many dynamic graph learning tasks. These models use node state vectors (i.e., memories) to capture and record graph changes (i.e., events), and then exploit these memories to assist prediction. However, this memorycentric design makes multi-GPU training challenging because predictions for later events often depend on memory updates from earlier events. To maintain model quality, existing multi-GPU TGNN training schemes strictly preserve all event dependencies, which limits parallelism and causes expensive cross-GPU memory synchronization. In this work, we observe that many of these dependencies can be handled more flexibly without harming training quality. Specifically, (a) dependencies in TGNN training have high locality in both time and graph topology, (b) the short-range dependencies missed within a large batch can often be recovered cheaply, and (c) many memory updates are not immediately needed. Based on these observations, we propose DepBloom to accelerate multi-GPU TGNN training with three techniques: (1) temporally bounded spatial partitioning to reduce unnecessary cross-GPU synchronization and improve parallelism; (2) intra-batch memory refinement to recover missing shortrange temporal dependencies inside enlarged batches; and
Keywords: Deep Learning, Dynamic Graph, Temporal Graph Neural Networks, Efficient Multi-GPU Training
1
Introduction
Dynamic graphs are widespread across various applications such as social networks [20], recommendation systems [38], traffic forecasting [24], and financial risk analysis [45]. Compared with static graphs, dynamic graphs involve changing nodes and edges, which makes representation learning substantially more challenging [2, 17, 21, 32]. Temporal Graph Neural Networks (TGNNs) have emerged as an effective approach for learning on dynamic graphs and have achieved state-of-the-art performance on a range of dynamic graph tasks [4, 8, 9, 19, 21, 27, 30, 32, 33, 35, 39, 42, 44, 46, 48, 50, 55]. TGNNs model a dynamic graph as a time-ordered sequence of events, where each event records a graph change, such as adding a node or an edge. A key feature of these models is that each node maintains a time-evolving state vector,
∗ Both authors contributed equally to this research.
1
Trovato et al.
Table 1. Comparison with representative efficient TGNN training systems under √ the two core challenges of scalable multi-GPU training. and ▲ denote explicit and partial support, respectively.
particular, we make three observations: First, dependencies in TGNN training are often local in both time and graph topology. This locality is hard to utilize with only one-dimensional partitioning. Temporal-only partitioning breaks topological dependencies while spatial-only partitioning degrades training quality over long horizons. Second, the short-range temporal dependencies missed inside a large batch can often be recovered cheaply. Specifically, stale node memories in a large batch can be recovered based on earlier events within the same batch, enabling higher parallelism while maintaining training quality. Third, memory updates are not equally urgent for subsequent computation. Only a small subset of updated node memories is immediately required by the next dependent batch. Therefore, uniformly synchronizing all updates places unnecessary work on the critical path and prolongs execution stalls. Together, these observations suggest that scalable TGNN training could preserve only critical dependencies while relaxing or restructuring the rest to improve parallelism and reduce synchronization. Based on these insights, we propose DepBloom, an efficient framework for scalable multi-GPU TGNN training with three key techniques. First, temporally bounded spatial partitioning divides the event stream into serial temporal windows and organizes each window into topology-aware parallel sub-chains, reducing unnecessary cross-GPU synchronization among sub-chains while preserving critical dependencies among windows. Second, intra-batch memory refinement recovers missing short-range temporal information inside enlarged batches, enabling higher parallelism without sacrificing training quality. Third, critical-path optimization for multi-GPU pipeline execution prioritizes urgent memory updates and removes non-critical updates and operations from the critical path, thereby improving pipeline execution efficiency and enhancing system scalability. Experimental results across diverse benchmarks show that DepBloom achieves an average speedup of 2.84× and up to 5.16× over baselines, while maintaining comparable or better model quality. We summarize our contributions as follows:
Quality-Aware Parallelism Memory Sync Overhead Batching Multi-GPU Scaling Reduce Sync Hide Sync √ ETC [13] √ Cascade [10] √ PipeTGL [26] ▲ DistTGL [55] ▲ ▲ √ √ √ √ DepBloom Work
often called node memory [7, 9, 10, 13, 26, 54], which is updated when relevant events occur around it. As dynamic graphs continue to grow in scale to billions or even trillions of events [22, 23, 54], efficient multi-GPU training of TGNNs is crucial for practical deployment. However, TGNN training is fundamentally bottlenecked by its unique memory update mechanism. Ideally, TGNNs follow a strict chronological execution order, updating node memories whenever they become relevant to an event [21, 33, 35, 42]. In TGNN training, however, events are grouped into batches, where each batch reads memories from earlier batches for computing and writes back updated memories for later batches [10, 21, 26, 32, 33, 35, 42, 54, 55]. As a result, unlike conventional deep learning workloads, where batches are largely independent, TGNN batches are linked by strict cross-batch memory dependencies, leading to two major challenges in scaling multi-GPU TGNN training. First, temporal dependency forces a trade-off between parallelism and training quality. Larger batches improve hardware utilization, but they delay memory updates and ignore dependencies among events within the same batch. Existing single-GPU TGNN systems, such as ETC and Cascade [10, 13], improve efficiency by enlarging batches along a chronological event stream while controlling information loss. However, simply enlarging batches remains insufficient to expose scalable parallelism across GPUs, while the resulting irregular workloads can further cause load imbalance and pipeline bubbles in multi-GPU execution. Second, multi-GPU scalability is limited by expensive crossGPU memory synchronization. Existing systems [7, 26] either synchronize updated memory states across GPUs at the end of each batch or ignore such synchronization altogether. As a result, they either incur substantial communication overhead and prolonged pipeline stalls, or suffer noticeable training-quality degradation. Table 1 summarizes how representative prior methods, together with our design, address these two core challenges. As the table shows, prior methods partially improve one challenge or the other, but remain insufficient for scalable multi-GPU TGNN training. Nevertheless, we find that many dependencies can be handled more flexibly without harming training quality. In
• We identify the excessive preservation of event dependencies in existing multi-GPU TGNN training frameworks as a major limitation of parallelism and scalability, and recognize the potential of handling these dependencies more flexibly without harming training quality. • We propose DepBloom, a multi-GPU TGNN training framework that combines temporally bounded spatial partitioning, intra-batch memory refinement, and critical-path optimization to increase parallelism and reduce cross-GPU synchronization costs. • We evaluate DepBloom on representative TGNN models and dynamic graph datasets, and show that it substantially outperforms prior multi-GPU TGNN training systems while maintaining comparable or better accuracy. 2
A Dependency-Aware Multi-GPU Training Framework for Temporal Graph Neural Networks node memory
Batch k-1 Batch k ti: add edge e23
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and similarly for node 𝑣𝑖 . Here, msg(·) denotes message construction and UPDT(·) denotes the memory update function. For prediction, TGNNs typically compute time-aware node embeddings by feeding the target node memory and its temporal neighborhood memories into a GNN module, e.g.,
node memory
h𝑢 (𝑡) = GNN s𝑢 (𝑡), {s𝑘 (𝑡) | 𝑘 ∈ N (𝑢, 𝑡)} ,
+ 𝑠2 (𝑡𝑖+1 )
Step 3: Memory updating
+ 𝑠4 (𝑡𝑖+1 )
followed by an MLP/scoring function to produce edge or node predictions. Batched TGNN Training. In practice, the input event sequence E = {𝑒𝑖 }𝑇𝑖=1 is divided into time-ordered batches 𝐾 and processed sequentially. Using edge prediction {B𝑘 }𝑘=1 as an example, Figure 1 shows that each batch B𝑘 has three stages: (a) First, in the embedding and prediction stage, the model fetches the pre-update memories of nodes involved in B𝑘 , denoted by S𝑘− = {s𝑣 (𝑡 − )}, and uses them to compute embeddings and predictions. Thus, all events in the same batch are predicted from memories updated in previous batches. (b) Next, in the message generation stage, the model generates messages from the current events and their pre-update memories according to Equation (1). (c) Finally, in the memory update stage, these messages are aggregated using a mean or most-recent operator [21, 32], and node memories are updated following Equation (1).
node memory
Figure 1. TGNN computing steps in one batch. In many TGNN training pipelines, the memory update of one batch is deferred and executed as the first step of the next batch.
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Background
2.1
Temporal GNN Learning on Dynamic Graphs
Dynamic Graphs. Dynamic graphs model systems whose nodes and edges evolve over time. They are commonly represented as either discrete-time dynamic graphs (DTDGs), modeled as a sequence of graph snapshots, or continuoustime dynamic graphs (CTDGs), modeled as a chronologically ordered stream of timestamped events. DTDGs can often be viewed as a coarser discretization of CTDG event streams, where events are grouped into time windows to form snapshots [9, 10, 54]. Recent work [1, 7, 10, 15, 26, 32, 52, 54] increasingly favors CTDGs because they preserve exact interaction timing and better capture fine-grained temporal dynamics. Formally, a CTDG is an ordered event sequence E = 𝑒 (𝑡 1 ), 𝑒 (𝑡 2 ), . . . with 𝑡 1 < 𝑡 2 < · · · , where each event denotes a timestamped graph interaction or update. Prediction at time 𝑡𝑖 is based on the event history before 𝑡𝑖 , which can be denoted as E𝑖− = 𝑒 (𝑡 1 ), . . . , 𝑒 (𝑡𝑖 −1 ). Temporal Graph Neural Networks. Temporal graph neural networks (TGNNs) maintain a time-evolving state vector for each node, commonly referred to as node memory [7, 10, 26, 32, 42, 54], to summarize its historical interactions for prediction. Formally, consider a chronologically ordered input event stream E = {𝑒𝑖 }𝑇𝑖=1 , where each event 𝑒𝑖 = (𝑢𝑖 , 𝑣𝑖 , 𝑡𝑖 , x𝑒𝑖 ) denotes an interaction between nodes 𝑢𝑖 and 𝑣𝑖 at time 𝑡𝑖 , optionally with edge features x𝑒𝑖 . TGNNs update node memories and use them for predictions as follows: When event 𝑒𝑖 arrives, the model first constructs messages using the pre-update memories of the two involved nodes, denoted by s𝑢−𝑖 and s𝑣−𝑖 , together with the time gap Δ𝑡𝑖 and edge features x𝑒𝑖 . It then updates the corresponding node memories. For example, the memory update for node 𝑢𝑖 can be written as m𝑣𝑖 𝑢𝑖 = msg(s𝑣−𝑖 , s𝑢−𝑖 , Δ𝑡𝑖 , x𝑒𝑖 ),
(2)
+ 𝑠3 (𝑡𝑖+1 )
2.2
Multi-GPU Training for TGNNs
To enable multi-GPU TGNN training, prior work has explored four representative paradigms [26, 55], as shown in Figure 2. Batch parallelism [53–55] executes adjacent batches concurrently on different GPUs, which improves throughput but causes stale memories by weakening interbatch dependencies. Epoch parallelism [55] overlaps different training epochs across GPUs, but later epochs may process the same samples before earlier model updates are fully incorporated. Memory parallelism [55] reduces synchronization by keeping multiple copies of node memory across GPUs, but this increases memory overhead and disrupts memory evolution across the entire training event stream. These three paradigms improve hardware utilization by relaxing the original dependency order of TGNN training. In contrast, pipeline parallelism [26] preserves dependency order while still exposing concurrency. It decomposes each batch into dependent stages, such as node memory update and node embedding, and overlaps different batches across GPUs. Once one batch finishes its memory update, the next GPU can start the following batch, while the current GPU continues the later stages of the current batch. Because it improves concurrency without violating the original update order, pipeline parallelism is the most suitable paradigm for TGNN training [26], and we focus on it in this work.
s𝑢+𝑖 = UPDT(s𝑢−𝑖 , m𝑣𝑖 𝑢𝑖 ), (1) 3
Trovato et al.
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Figure 2. Comparison of four multi-GPU training paradigms for TGNNs: (a) batch parallelism, (b) epoch parallelism, (c) memory parallelism, and (d) pipeline parallelism. Here, 𝐵𝑖𝑗 denotes the 𝑗-th batch in epoch 𝑖, and different colors distinguish batches from different epochs. RW denotes memory read and write operations, where different colors indicate different memory copies. Green arrows indicate inter-GPU data movement.
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Motivation and Opportunity
3.1
Bottlenecks in Multi-GPU TGNN Training
batch-centric designs are effective for single-GPU execution, but expose parallelism only along a single global event stream: once a dependency reaches the batch boundary, unrelated graph regions cannot progress independently. Meanwhile, irregular dependency-aware batch sizes can cause workload imbalance and bubbles across GPUs, limiting multiGPU scalability. Consequently, existing multi-GPU TGNN systems still rely on relatively small batches to preserve quality [26, 55], which in turn increases synchronization frequency and leads to frequent stalls on memory updates.
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