January 2026 (Month: 2026-01) — OpenXiangShan/GEM5: Delivered a production-grade trace-driven simulation framework for the O3 CPU architecture, enabling high-fidelity performance modeling with ChampSim and CBP2025 traces. The initiative spanned trace infrastructure, readers, configuration, and end-to-end pipeline integration, resulting in reproducible, faster research cycles and more accurate performance insights. Alongside, robust tracing tooling and documentation were established to support researchers and accelerate experiments.

June 2025: Delivered targeted documentation enhancement for ISCA'25 tutorial scheduling in OpenXiangShan/XiangShan-doc. Clarified session timings across the introduction, XiangShan project overview, XS-Gem5 simulator, microarchitecture design, and hands-on development, enabling attendees to plan effectively. The update is captured in a dedicated docs commit tied to PR #196, ensuring traceability.

September 2023 — OpenXiangShan/GEM5 monthly summary focused on instrumentation and observability improvements for the CPU branch-prediction path. Delivered a BTB database tracing and logging feature to enable detailed BTB event logging, laying groundwork for data-driven performance tuning and faster root-cause analysis. No major bugs fixed this month; effort centering on instrumentation rather than feature regressions. Impact includes improved visibility into prediction behavior, enabling more precise performance optimizations and safer progress tracking. Technologies demonstrated include CPU architecture instrumentation, Branch Target Buffer (BTB) design, logging/database integration, and GEM5 development workflows. Business value lies in reduced MTTR for predictor-related issues, better data for optimization decisions, and stronger monitoring of performance regressions.

In 2023-08, OpenXiangShan/GEM5 delivered targeted BTB (Branch Target Buffer) improvements and a critical bug fix, enhancing branch prediction accuracy and the reliability of simulation-derived performance insights. The work focused on BTB Prediction Enhancement and Accuracy Improvements and a Bug Fix for Correct Entry Counting. These changes strengthen the fidelity of architectural exploration for OpenXiangShan on GEM5.

In July 2023, delivered a substantial enhancement to the processor branch prediction subsystem within the OpenXiangShan/GEM5 project, introducing a multi-way BTB predictor with Return Address Stack (RAS) and TAGE support, and integrating ITTAGE parameters into the predictor framework. This work consolidates and extends prediction accuracy, enabling more dynamic speculative behavior and reducing misprediction penalties across representative workloads. Changes are backed by two commits: 019404c343829a5fc61f781140dae1e6ad3cabd1 (btb-pred: add multi-way btb pred with ras and tage, other predictors to be added) and 3ca0cef27231a0f4abe6c1acf340e8dc09514f0c (btb-pred: add ittage support). Overall, the month delivered technical progress with clear value for performance and a solid foundation for further predictor enhancements.