https://www.yunwei37.com/blog Yusheng Zheng is a systems researcher working on GPU runtimes, distributed AI infrastructure, programmable systems, and agent observability. en-us yunwei356@gmail.com (Yusheng Zheng) yunwei356@gmail.com (Yusheng Zheng) Sat, 19 Sep 2026 15:30:00 GMT https://www.yunwei37.com/blog/deepseek-v41-engram-nowait-dgx-spark https://www.yunwei37.com/blog/deepseek-v41-engram-nowait-dgx-spark A production investigation of DeepSeek V4.1 disk-backed Engram on four DGX Sparks: how syscall, page-cache, and component profiling found a Python scheduling bottleneck, how RWF_NOWAIT fixed it, and what the production evidence does and does not prove. Sat, 19 Sep 2026 15:30:00 GMT yunwei356@gmail.com (Yusheng Zheng) llm-inferencedeepseekvllmlinuxstorageprofiling