OpenXiangShan/GEM5
Oct 2025 – Jan 2026
4 Months active
Languages Used
C++Python
Technical Skills
Branch PredictionCPU ArchitecturePerformance OptimizationSystem SimulationC++ programmingdebugging
Cao Jiaming
PROFILE
Cao Jiaming
Overall Statistics
Feature vs Bugs
100%Features
Repository Contributions
14Total
Bugs
0
Commits
14
Features
5
Lines of code
1,364
Activity Months4
Your Network
40 people
Work History
January 2026
2 Commits • 1 Features
Jan 1, 2026January 2026 (OpenXiangShan/GEM5) focused on streamlining the branch prediction and BTB (branch target buffer) pipeline to improve simulation accuracy and maintainability. Core efforts were centered around consolidating predwrongSource handling for wrong-source predictions, aligning BTB entry processing with stage-based predictions, and removing legacy basetable logic to simplify the code path. Key results include a refactored BTB/prediction path that consolidates source handling, the introduction of wrong-prediction statistics for improved diagnostic visibility, and a marked reduction in dead/unused code by removing basetable logic from BTBTAGE and MBTB and related components.
2 Commits • 1 Features
Jan 1, 2026January 2026 (OpenXiangShan/GEM5) focused on streamlining the branch prediction and BTB (branch target buffer) pipeline to improve simulation accuracy and maintainability. Core efforts were centered around consolidating predwrongSource handling for wrong-source predictions, aligning BTB entry processing with stage-based predictions, and removing legacy basetable logic to simplify the code path. Key results include a refactored BTB/prediction path that consolidates source handling, the introduction of wrong-prediction statistics for improved diagnostic visibility, and a marked reduction in dead/unused code by removing basetable logic from BTBTAGE and MBTB and related components.
January 2026
December 2025
9 Commits • 2 Features
Dec 1, 2025December 2025: Delivered substantial branch predictor enhancements in GEM5 (OpenXiangShan) with focus on accuracy, configurability, and observability across ITTAGE/TAGE and UBTB/BTB. Key outcomes include ABTB configurability, S3 prediction handling, misprediction counters, and expanded commit statistics across ITTAGE/BTB components, supported by cleanup efforts. MBTB basetable alignment and integration progressed with fixed-target statistics and support for a choice MBTB basetable, boosting accuracy and analytics. Backend refactors and bug fixes across ABTB/MBTB/UBTB improved coherence and reduced debt. Overall business impact: more reliable performance modeling, faster tuning, and better decision support for architecture exploration. Technologies demonstrated: C++, hardware simulation internals, performance analytics, and collaborative git workflows across multiple contributors.
December 2025
9 Commits • 2 Features
Dec 1, 2025December 2025: Delivered substantial branch predictor enhancements in GEM5 (OpenXiangShan) with focus on accuracy, configurability, and observability across ITTAGE/TAGE and UBTB/BTB. Key outcomes include ABTB configurability, S3 prediction handling, misprediction counters, and expanded commit statistics across ITTAGE/BTB components, supported by cleanup efforts. MBTB basetable alignment and integration progressed with fixed-target statistics and support for a choice MBTB basetable, boosting accuracy and analytics. Backend refactors and bug fixes across ABTB/MBTB/UBTB improved coherence and reduced debt. Overall business impact: more reliable performance modeling, faster tuning, and better decision support for architecture exploration. Technologies demonstrated: C++, hardware simulation internals, performance analytics, and collaborative git workflows across multiple contributors.
November 2025
2 Commits • 1 Features
Nov 1, 2025November 2025 — OpenXiangShan/GEM5: Delivered internal branch prediction (ABTB) debugging enhancements and targeted UBTB/TAGE improvements to strengthen debugging capabilities, reliability, and microarchitectural performance. Implemented a dedicated ABTB debug flag, cleaned up legacy code for maintainability, and improved misprediction handling within the TAGE path. Addressed UBTB-related bugs to improve accuracy and measurement fidelity, enabling faster diagnosis and iteration for future optimizations.
2 Commits • 1 Features
Nov 1, 2025November 2025 — OpenXiangShan/GEM5: Delivered internal branch prediction (ABTB) debugging enhancements and targeted UBTB/TAGE improvements to strengthen debugging capabilities, reliability, and microarchitectural performance. Implemented a dedicated ABTB debug flag, cleaned up legacy code for maintainability, and improved misprediction handling within the TAGE path. Addressed UBTB-related bugs to improve accuracy and measurement fidelity, enabling faster diagnosis and iteration for future optimizations.
November 2025
October 2025
1 Commits • 1 Features
Oct 1, 2025OpenXiangShan/GEM5 (2025-10) focused on a targeted performance enhancement by integrating MicroTAGE into the S1 stage of the CPU pipeline. This work adds a MicroTAGE branch predictor to S1, updates predictor configuration, and refactors code for maintainability and easier integration with existing branch-prediction logic. The effort delivers a concrete architectural advancement for dynamic branch prediction, ready for broader evaluation and future optimization. Delivered commit: 340af13e8310dbbcdf9797b1d77ead2159321d2b ("Microtage on s1 perf (#567)").
October 2025
1 Commits • 1 Features
Oct 1, 2025OpenXiangShan/GEM5 (2025-10) focused on a targeted performance enhancement by integrating MicroTAGE into the S1 stage of the CPU pipeline. This work adds a MicroTAGE branch predictor to S1, updates predictor configuration, and refactors code for maintainability and easier integration with existing branch-prediction logic. The effort delivers a concrete architectural advancement for dynamic branch prediction, ready for broader evaluation and future optimization. Delivered commit: 340af13e8310dbbcdf9797b1d77ead2159321d2b ("Microtage on s1 perf (#567)").
Activity
Loading activity data...
Quality Metrics
Correctness85.8%
Maintainability82.8%
Architecture82.8%
Performance81.4%
AI Usage31.4%
Skills & Technologies
Programming Languages
C++Python
Technical Skills
Branch PredictionC++ developmentC++ programmingCPU ArchitecturePerformance OptimizationSystem Simulationalgorithm designbranch prediction algorithmsdebuggingmicroarchitectureperformance optimizationstatistical analysisstatistics trackingsystem designsystem programming
Repositories Contributed To
Overview of all repositories you've contributed to across your timeline