Decoding throughput gains from larger inference batches are often limited by GPU memory, mainly due to the large size of KV cache. Training-free KV cache offloading mitigates this issue by storing redundant context on the CPU and fetching sparse KV subsets, but often harms long-generation quality due to training-inference mismatch of sparse patterns. Trainable sparse attention can improve quality, yet its unconstrained KV accesses are inefficient for offloading and may incur excessive CPU–GPU transfers. To this end, we propose NOSA, a trainable sparse attention mechanism designed for KV cache offloading. NOSA explicitly bounds CPU–GPU KV transfers, enabling low communication overhead and high decoding throughput. We further develop NOSI, an offloading inference system that realizes these efficiency gains. Experiments on 1,3,8B LLMs show that NOSA outperforms KV cache offloading baselines on general, long-input, and long-generation tasks, while improving decoding throughput by up to 5.04×, 1.92×, and 1.83× over FullAttn, InfLLMv2, and ShadowKV, respectively.

Modern language models increasingly adopt hybrid architectures that combine full attention with efficient attention modules, such as sliding-window attention (SWA) and recurrent sequence mixers. However, how these efficient modules shape model capabilities remains poorly understood. To address this gap, we conduct a systematic analysis across hybrid architectures from three perspectives: scaling behavior, mechanism analysis, and architecture design. First, from a scaling perspective, we find that efficient-attention design primarily affects how fast long-context capability emerges, while different hybrids eventually converge to comparable long-context performance under sufficient training. Second, mechanistically, we show that long-range retrieval is mainly carried by full attention, whereas efficient attention shapes its optimization trajectory. This explains a counter-intuitive phenomenon we call Large-Window Laziness: larger SWA windows can delay the formation of retrieval heads in full-attention layers. Third, guided by this mechanism, we show that applying No Positional Encoding (NoPE) to only the full-attention layers of a small-window SWA hybrid substantially improves long-context performance with negligible impact on short-context performance.

Large language model agents have enabled GUI-based automation, particularly for mobile devices. However, deployment remains limited by noisy data, poor generalization, and lack of support for non-English GUIs. In this work, we present AgentCPM-GUI, an 8B-parameter GUI agent built for robust and efficient on-device GUI interaction. Our training pipeline includes grounding-aware pre-training to enhance perception, supervised fine-tuning on high-quality Chinese and English trajectories to imitate human-like actions, and reinforcement fine-tuning with GRPO to improve reasoning capability. AgentCPM-GUI achieves promising performance on five public benchmarks and our proposed Chinese benchmark CAGUI. To facilitate reproducibility and further research, we publicly release all code, model checkpoint, and evaluation data at: https://github.com/OpenBMB/AgentCPM-GUI