Web browsing—widely used for information retrieval and fact verification—has become a fundamental capability of recently emerged large language model (LLM) agents, which is often elicited by training on complex questions requiring web search. However, this task faces challenges with respect to data and training: existing QA datasets are mostly 1-3 hop over closed corpora (e.g., Wikipedia); meanwhile, outcome-based on-policy RL that used by recent works is inefficient and brittle in long-horizon, tool-heavy browsing environments. To address these challenges, we introduce GraphSynthQA, a knowledge-graph (KG)—guided synthesis framework in an open-web setting. Starting from Wikidata seed entities, GraphSynthQA iteratively retrieves and verifies evidence from the internet to expand a KG, then synthesizes complex, answer-verifiable queries grounded in multi-evidence dependencies. Building on the synthesized data, we train web-browsing agents with a compute-efficient two-stage recipe: (i) cold-start supervised fine-tuning on ReAct-style trajectories, and (ii) step-level Direct Preference Optimization (DPO), where preferences are constructed offline via single-step branched rollouts that contrast candidate actions by their downstream success rates, providing dense process supervision without expensive on-policy exploration. Experiments show that our approach consistently improves performance on challenging web-browsing benchmarks and remains competitive among models of similar size.

Distributed Deep Learning (DDL) is widely used to accelerate deep neural network training for various Web applications. In each iteration of DDL training, each worker synchronizes neural network gradients with other workers. This introduces communication overhead and degrades the scaling performance. In this paper, we propose a recursive model, OSF (Scaling Factor considering Overlap), for estimating the scaling performance of DDL training of neural network models, given the settings of the DDL system. OSF captures two main characteristics of DDL training: the overlap between computation and communication, and the tensor fusion for batching updates. Measurements on a real-world DDL system show that OSF obtains a low estimation error (ranging from 0.5% to 8.4% for different models). Using OSF, we identify the factors that degrade the scaling performance, and propose solutions to effectively mitigate their impacts. Specifically, the proposed adaptive tensor fusion improves the scaling performance by 32.2%∼ 150% compared to the constant tensor fusion buffer size.

Programmable switches are recently used for accelerating data-intensive distributed applications. Some computational tasks, traditionally performed on servers in data centers, are offloaded to the network on programmable switches. These tasks may require the support of on-the-fly floatingpoint operations. Unfortunately, the computational capacity of programmable switches is limited to simple integer arithmetic operations. To address this issue, prior approaches either adopt a float-to-integer method or rely on local CPUs of switches, incurring accuracy loss and delayed processing.To this end, we propose NetFC, a table-lookup method to achieve on-the-fly in-network floating-point arithmetic operations nearly without accuracy loss. NetFC adopts a divide-and-conquer mechanism that converts the original huge table into several much smaller tables that are operated by the built-in integer operations. NetFC further leverages a scaling-factor mechanism for improving computational accuracy, and a prefix-based lossless table compression method to reduce memory consumption. We use both synthetic and real-life datasets to evaluate NetFC. The experimental results show that the average accuracy of NetFC is above 99.94% with only 448KB memory consumption. Furthermore, we integrate NetFC into Sonata [12] for detecting Slowloris attack, yielding significant decrease of detection delay.

Recent years have witnessed a growing list of systems for distributed data-parallel training. Existing systems largely fit into two paradigms, i.e., parameter server and MPI-style collective operations. On the algorithmic side, researchers have proposed a wide range of techniques to lower the communication via "system relaxations": quantization, decentralization, and communication delay. However, most, if not all, existing systems only rely on standard synchronous and asynchronous stochastic gradient (SG) based optimization, therefore, cannot take advantage of all possible optimizations that the machine learning community has been developing recently. Given this emerging gap between the current landscapes of systems and theory, we build Bagua, a MPI-style communication library, providing a collection of primitives, that is both flexible and modular to support state-of-the-art system relaxation techniques of distributed training. Powered by this design, Bagua has a great ability to implement and extend various state-of-the-art distributed learning algorithms. In a production cluster with up to 16 machines (128 GPUs), Bagua can outperform PyTorch-DDP, Horovod and BytePS in the end-to-end training time by a significant margin (up to 2X) across a diverse range of tasks. Moreover, we conduct a rigorous tradeoff exploration showing that different algorithms and system relaxations achieve the best performance over different network conditions.