Ion Stoica

Recent advances in prompt learning allow large language model agents to acquire task-relevant knowledge from inference-time context without parameter changes. For example, existing methods (like ACE or GEPA) can learn system prompts to improve accuracy based on previous agent runs. However, these methods primarily focus on single-agent or low-parallelism settings. This fundamentally limits their ability to efficiently learn from a large set of collected agentic traces. It would be efficient and beneficial to run prompt learning in parallel to accommodate the growing trend of learning from many agentic traces or parallel agent executions. Yet without a principled strategy for scaling, current methods suffer from quality degradation with high parallelism. To improve the quality delay tradeoff of prompt learning, we propose Combee, a plug-and-play framework that scales parallel prompt learning on top of existing methods such as ACE and GEPA. Combee speeds up learning and enables running many agents in parallel while preserving most of the quality of sequential learning from their aggregate traces. To achieve this, Combee leverages parallel scans and employs an augmented shuffle mechanism; Combee also introduces a dynamic batch size controller to balance quality and delay. Evaluations on AppWorld, Terminal-Bench, Formula, and FiNER demonstrate that Combee substantially improves the quality delay tradeoff of prompt learning, achieving up to 17× speedup over previous methods at equivalent cost while matching or approaching their best accuracy.

Recent work such as AlphaEvolve has shown that combining LLM-driven optimization with evolutionary search can effectively improve programs, prompts, and algorithms across domains. In this paradigm, previously evaluated solutions are reused to guide the model toward new candidate solutions. Crucially, the effectiveness of this evolution process depends on the search strategy: how prior solutions are selected and varied to generate new candidates. However, most existing methods rely on fixed search strategies with predefined knobs (e.g., explore–exploit ratios) that remain static throughout execution. While effective in some settings, these approaches often fail to adapt across tasks, or even within the same task as the search space changes over time. We introduce EvoX, an adaptive evolution method that optimizes its own evolution process. EvoX jointly evolves candidate solutions and the search strategies used to generate them, continuously updating how prior solutions are selected and varied based on progress. This enables the system to dynamically shift between different strategies during the optimization process. Across nearly 200 real-world optimization tasks, EvoX consistently outperforms prior open frameworks, including OpenEvolve, ShinkaEvolve, and GEPA. It achieves the best open-source performance on Frontier-CS (+34\% median over the best AI solutions across 172 problems), matches or surpasses AlphaEvolve and human-designed state-of-the-art solutions on multiple benchmarks, and does so at more than 3$\times$ lower cost on average compared to existing open systems and Claude Code.

Large Language Models (LLMs) are emerging as a promising approach for discovery problems in mathematics and systems optimization. Existing search algorithms keep models frozen, yet applying reinforcement learning (RL) over full search trajectories spanning hundreds of refinement steps remains difficult. We present KTPO (K-Step Test-Time Policy Optimization), which addresses this challenge by training on short trajectories of k refinement steps. To retain the benefits of longer search, each trajectory starts from a previously discovered program rather than from scratch. In particular, KTPO selects programs near the model’s current capability frontier, estimated by the model’s improvement rate over existing programs. KTPO with 4B-9B models achieves strong performance across seven mathematical and systems optimization tasks. On mathematical problems, KTPO outperforms or approaches the human record on Circle Packing and the Erd˝os minimum overlap problem. On systems optimization tasks from ADRS, a benchmark suite for real-world systems optimization, KTPO out- performs human record on maximizing SQL query prefix hit rate, and surpasses the prior AI records on minimizing multi-cloud data transfer cost and on balancing expert-parallel load across GPUs. Code is available at https://github.com/DachengLi1/KTPO.

The ability to research and synthesize knowledge is central to human expertise and progress. A new class of AI systems—designed for generative research synthesis—aims to automate this process by retrieving information from the web and producing long-form, cited reports. Yet, evaluating such systems remains an open challenge: existing question-answering benchmarks focus on short, factual answers, while expert-curated datasets risk staleness and data contamination. Neither captures the complexity and evolving nature of real research synthesis tasks. We introduce DeepScholar-bench, a live benchmark and automated evaluation framework for generative research synthesis. DeepScholar-bench draws queries and human-written exemplars from recent, high-quality ArXiv papers and evaluates a real synthesis task: generating a related work section by retrieving, synthesizing, and citing prior work. Our automated framework holistically measures performance across three key dimensions—knowledge synthesis, retrieval quality, and verifiability. To further future work, we also contribute DeepScholar-ref, a simple, open-source reference pipeline, which is implemented on the LOTUS framework and provides a strong baseline. Using DeepScholar-bench, we systematically evaluate prior open-source systems, search agents with strong models, OpenAI’s DeepResearch, and DeepScholar-ref. We find DeepScholar-bench is far from saturated: no system surpasses a geometric mean of 31% across all metrics. These results highlight both the difficulty and importance of DeepScholar-bench as a foundation for advancing AI systems capable of generative research synthesis.

Modern Mixture-of-Experts (MoE) workloads rely on expert parallelism (EP) to achieve high GPU efficiency. State-of-the-art EP communication libraries, such as DeepEP, rely on GPU-initiated RDMA communication. Although performant, they have poor portability across heterogeneous GPU and NIC hardwar...

Fast-evolving machine learning (ML) workloads have increasing requirements for networking. However, host network transport on RDMA NICs is hard to evolve, causing problems for ML workloads. For example, single-path RDMA traffic is prone to flow collisions that severely degrade collective communic...

This paper presents a set of in-process and remote distributed caches for datacenter environments, CLINK and CRINK respectively, that provide linearizable reads entirely from memory without contacting storage. These caches remain loosely coupled to the storage layer and achieve high performance,...