Core Viewpoint - Reinforcement Learning (RL) is transitioning from a supportive technology to a core driver of model capabilities, focusing on multi-step, interactive agent training to achieve General Artificial Intelligence (AGI) [2][6]. Group 1: Modern RL Infrastructure Architecture - The core components of modern RL infrastructure include a Generator, which interacts with the environment to generate trajectories and calculate rewards, and a Trainer, which updates model parameters based on trajectory data [6][4]. - The generator-trainer architecture, combined with distributed coordination layers like Ray, forms the "gold standard" for RL systems [6][4]. Group 2: Primary Development - Primary Development frameworks serve as foundational frameworks for building RL training pipelines, providing core algorithm implementations and integration with underlying training/inference engines [8][7]. - TRL (Transformer Reinforcement Learning) is a user-friendly RL framework launched by Hugging Face, offering various algorithm supports [9][10]. - OpenRLHF, developed by a collaborative team including ByteDance and NetEase, aims to provide an efficient and scalable RLHF and Agentic RL framework [11][14]. - veRL, developed by Byte's Seed team, is one of the most comprehensive frameworks with extensive algorithm support [16][19]. - AReaL (Asynchronous Reinforcement Learning) is designed for large-scale, high-throughput RL training with a fully asynchronous architecture [20][21]. - NeMo-RL, launched by NVIDIA, integrates into its extensive NeMo ecosystem, focusing on production-level RL frameworks [24][28]. - ROLL, an Alibaba open-source framework, emphasizes asynchronous and Agentic capabilities for large-scale LLM RL [30][33]. - slime, developed by Tsinghua and Zhipu, is a lightweight framework focusing on seamless integration of SGLang with Megatron [34][36]. Group 3: Secondary Development - Secondary Development frameworks are built on primary frameworks, targeting specific downstream application scenarios like multi-modal, multi-agent, and GUI automation [44][3]. - Agentic RL frameworks, such as verl-agent, optimize for asynchronous rollout and training, addressing the core challenges of multi-round interactions with external environments [46][47]. - Multimodal RL frameworks, like VLM-R1 and EasyR1, focus on training visual-language reasoning models, addressing data processing and loss function design challenges [53][54]. - Multi-Agent RL frameworks, such as MARTI, integrate multi-agent reasoning and reinforcement learning for complex collaborative tasks [59][60]. Group 4: Summary and Trends - The RL infrastructure is evolving from a "workshop" model to a "standardized pipeline," with increasing modularity in framework design [65]. - Asynchronous architectures are becoming essential to address the computational asymmetry between rollout and training [66]. - The emergence of high-performance inference engines like vLLM and SGLang significantly accelerates the rollout process [66]. - The evolution from RLHF to Agentic RL reflects the growing complexity of tasks supported by new frameworks [66]. - Distributed training framework choices, such as Megatron-LM and DeepSpeed, are critical for large-scale model training [66]. - Scene-driven secondary development frameworks are addressing unique challenges in vertical domains [66]. - The importance of orchestrators for managing distributed components in RL systems is becoming widely recognized [66].