google/perfetto
Oct 2024 – Oct 2025
11 Months active
Languages Used
SQLTypeScriptprotobufsqlC++MarkdownGNProto
Technical Skills
Code RefactoringData VisualizationPerformance TracingProtocol BuffersSQLTypeScript Development
Simon MacMullen
PROFILE
Simon Macmullen
Simon MacMullen contributed to the google/perfetto repository by building and refining advanced tracing and analytics features for Android system performance. He engineered per-UID CPU usage tracking, modular battery tracing plugins, and enhanced data visualization in the UI, using C++, SQL, and TypeScript. Simon’s work included refactoring core libraries for maintainability, optimizing SQL queries for large-scale trace analysis, and implementing robust error handling for kernel wakelock data. By integrating new data sources and improving concurrency safety, he enabled more granular, reliable performance diagnostics. His engineering demonstrated depth in system programming, data processing, and end-to-end trace pipeline improvements across Perfetto.
Overall Statistics
Feature vs Bugs
67%Features
Repository Contributions
38Total
Bugs
8
Commits
38
Features
16
Lines of code
20,129
Activity Months11
Your Network
4376 people
Work History
October 2025
1 Commits • 1 Features
Oct 1, 2025October 2025 monthly summary for google/perfetto: Delivered the Day Explorer: Display Device Usage Data feature, updating the data source from behaviors to device usages. This included renaming functions and SQL queries to reflect the new data source and applying capitalization fixes in the UI. The change is captured in commit f3b1787ab1aba6c27dc97c0e4cb704137f0bba26 with message "Update Day Explorer plugin to read usages, not behaviors. (#3100)".
1 Commits • 1 Features
Oct 1, 2025October 2025 monthly summary for google/perfetto: Delivered the Day Explorer: Display Device Usage Data feature, updating the data source from behaviors to device usages. This included renaming functions and SQL queries to reflect the new data source and applying capitalization fixes in the UI. The change is captured in commit f3b1787ab1aba6c27dc97c0e4cb704137f0bba26 with message "Update Day Explorer plugin to read usages, not behaviors. (#3100)".
October 2025
September 2025
8 Commits • 4 Features
Sep 1, 2025September 2025 performance summary for google/perfetto focusing on delivering high-value tracing capabilities, improving data accuracy, and boosting performance through modular architecture and targeted optimizations.
September 2025
8 Commits • 4 Features
Sep 1, 2025September 2025 performance summary for google/perfetto focusing on delivering high-value tracing capabilities, improving data accuracy, and boosting performance through modular architecture and targeted optimizations.
August 2025
2 Commits • 1 Features
Aug 1, 2025Monthly work summary for 2025-08 focused on delivering granular CPU usage analytics and improving the data path for per-UID tracing in Perfetto. Key outcomes include the introduction of Per-UID CPU Usage Analytics with On-Demand Emission for the google/perfetto repository, refactoring CPU-per-UID sources into a reusable utility, and restructuring the package list data source into parsing and writing phases. A new Trace Processor module and counter enable granular per-UID tracking. Commits implementing these changes include 6960e45b303439c35e06af05d763869bda646d8f (Add "on use" mode for packages list data source. (#2365)) and b123a57949ead368fd3013f675415fcb22f24a1d (Add support for CPU-per-UID data source to Trace Processor (#1983)).
2 Commits • 1 Features
Aug 1, 2025Monthly work summary for 2025-08 focused on delivering granular CPU usage analytics and improving the data path for per-UID tracing in Perfetto. Key outcomes include the introduction of Per-UID CPU Usage Analytics with On-Demand Emission for the google/perfetto repository, refactoring CPU-per-UID sources into a reusable utility, and restructuring the package list data source into parsing and writing phases. A new Trace Processor module and counter enable granular per-UID tracking. Commits implementing these changes include 6960e45b303439c35e06af05d763869bda646d8f (Add "on use" mode for packages list data source. (#2365)) and b123a57949ead368fd3013f675415fcb22f24a1d (Add support for CPU-per-UID data source to Trace Processor (#1983)).
August 2025
July 2025
1 Commits
Jul 1, 2025Monthly performance summary for 2025-07 focused on strengthening concurrency safety in the Metatrace subsystem of google/perfetto. Delivered a thread-local refactor to enable safe multi-threaded usage and to prevent cross-thread state leakage within the tracing pipeline.
July 2025
1 Commits
Jul 1, 2025Monthly performance summary for 2025-07 focused on strengthening concurrency safety in the Metatrace subsystem of google/perfetto. Delivered a thread-local refactor to enable safe multi-threaded usage and to prevent cross-thread state leakage within the tracing pipeline.
June 2025
2 Commits • 1 Features
Jun 1, 2025June 2025 monthly summary for google/perfetto: Delivered a new data source for CPU time collection by UID and CPU cluster, enabling granular attribution of CPU usage to apps and system components. Implemented configurations, data structures, and probes to support per-UID CPU time tracking, boosting observability and performance diagnostics. Fixed a permission-related initialization issue by removing an explicit startTrackingUidTimes() call, reducing setup complexity and potential failures.
2 Commits • 1 Features
Jun 1, 2025June 2025 monthly summary for google/perfetto: Delivered a new data source for CPU time collection by UID and CPU cluster, enabling granular attribution of CPU usage to apps and system components. Implemented configurations, data structures, and probes to support per-UID CPU time tracking, boosting observability and performance diagnostics. Fixed a permission-related initialization issue by removing an explicit startTrackingUidTimes() call, reducing setup complexity and potential failures.
June 2025
May 2025
6 Commits • 3 Features
May 1, 2025May 2025 monthly summary for google/perfetto. Delivered three key features enhancing battery tracing and analytics, plus robust improvements to data quality and testing. Highlights include: AndroidLongBatteryTracing Refactor and Enablement—grouped device state tracks under a common 'Device State' group, removed unused allowlist, and re-enabled long battery tracing across all traces; Day Explorer UI for battery blame data—adds Day Explorer to Perfetto UI to view categorized energy and behavioral data with improved defaults; Kernel wakelocks data quality and testing improvements—fixes for duration calculations, exposes awake duration, corrects GROUP BY behavior after renames, adds defensive checks, and introduces difftest coverage. Major bugs fixed centered on wakelocks data reliability, yielding more accurate power analyses. Overall impact includes more reliable battery analytics, faster debugging of power issues, and stronger test coverage. Technologies/skills demonstrated include Android tracing, Perfetto data modeling, UI integration, data quality engineering, and difftest testing.
May 2025
6 Commits • 3 Features
May 1, 2025May 2025 monthly summary for google/perfetto. Delivered three key features enhancing battery tracing and analytics, plus robust improvements to data quality and testing. Highlights include: AndroidLongBatteryTracing Refactor and Enablement—grouped device state tracks under a common 'Device State' group, removed unused allowlist, and re-enabled long battery tracing across all traces; Day Explorer UI for battery blame data—adds Day Explorer to Perfetto UI to view categorized energy and behavioral data with improved defaults; Kernel wakelocks data quality and testing improvements—fixes for duration calculations, exposes awake duration, corrects GROUP BY behavior after renames, adds defensive checks, and introduces difftest coverage. Major bugs fixed centered on wakelocks data reliability, yielding more accurate power analyses. Overall impact includes more reliable battery analytics, faster debugging of power issues, and stronger test coverage. Technologies/skills demonstrated include Android tracing, Perfetto data modeling, UI integration, data quality engineering, and difftest testing.
April 2025
2 Commits • 1 Features
Apr 1, 2025April 2025: Perfetto delivered two high-value changes in google/perfetto that improve UX relevance and data integrity for tracing. - Feature: Long Battery UX conditional rendering. Only show the long battery user experience for allowed trace session names to avoid noise and irrelevant information. Commit 4734f3abe271775d3cf85ae549c2fb8ff81932bc (#1148). - Bug fix: Kernel wakelock data anomaly handling. Detect, ignore, and log unusual results from SuspendControlService; introduce error flags to detect zero or non-monotonic values and prevent corrupt trace data. Commit 791082540417679112576973dea16ce801aa95c2 (#1166). Overall impact: Higher data quality, reduced UI noise, and faster troubleshooting for battery-related tracing; more reliable wakelock data. Technologies demonstrated: UI conditional rendering, anomaly detection and logging, error flagging, tracing/data integrity, C++ Perfetto codebase.
2 Commits • 1 Features
Apr 1, 2025April 2025: Perfetto delivered two high-value changes in google/perfetto that improve UX relevance and data integrity for tracing. - Feature: Long Battery UX conditional rendering. Only show the long battery user experience for allowed trace session names to avoid noise and irrelevant information. Commit 4734f3abe271775d3cf85ae549c2fb8ff81932bc (#1148). - Bug fix: Kernel wakelock data anomaly handling. Detect, ignore, and log unusual results from SuspendControlService; introduce error flags to detect zero or non-monotonic values and prevent corrupt trace data. Commit 791082540417679112576973dea16ce801aa95c2 (#1166). Overall impact: Higher data quality, reduced UI noise, and faster troubleshooting for battery-related tracing; more reliable wakelock data. Technologies demonstrated: UI conditional rendering, anomaly detection and logging, error flagging, tracing/data integrity, C++ Perfetto codebase.
April 2025
March 2025
2 Commits
Mar 1, 2025Monthly summary for 2025-03 for google/perfetto focusing on reliability improvements: delivered critical wakelock analysis bug fixes and improved log-scale tooltip accuracy, with traceable commits. Impact: more robust data, fewer anomalies, clearer visualization for users.
March 2025
2 Commits
Mar 1, 2025Monthly summary for 2025-03 for google/perfetto focusing on reliability improvements: delivered critical wakelock analysis bug fixes and improved log-scale tooltip accuracy, with traceable commits. Impact: more robust data, fewer anomalies, clearer visualization for users.
January 2025
8 Commits • 2 Features
Jan 1, 2025January 2025 monthly summary for google/perfetto: Highlights include delivering kernel wakelocks data source with ingestion and delta-encoded duration optimization; refactoring wakeup and screen state analysis into the core library; and a network type detection fix for Android long battery tracing. These work items improved power profiling accuracy, data processing performance, and maintainability, driving better energy insights and more reliable network metrics in production.
8 Commits • 2 Features
Jan 1, 2025January 2025 monthly summary for google/perfetto: Highlights include delivering kernel wakelocks data source with ingestion and delta-encoded duration optimization; refactoring wakeup and screen state analysis into the core library; and a network type detection fix for Android long battery tracing. These work items improved power profiling accuracy, data processing performance, and maintainability, driving better energy insights and more reliable network metrics in production.
January 2025
November 2024
4 Commits • 1 Features
Nov 1, 2024November 2024: Stabilized Perfetto data flow and visuals through targeted bug fixes, a documentation improvement, and a reliability enhancement in slice handling. Delivered four key items: unknown enum handling in the proto-to-args parser; independent y-axes for battery_stats visualizations; suspend_enter slice termination bug fix via a new state machine; and documentation for update-statsd-descriptor usage. Impact: reduced data type errors, improved visualization accuracy, and more robust slice lifecycle, enabling better performance analysis and faster onboarding. Technologies/skills demonstrated: parser robustness, visualization axis management, state-machine design, code refactoring, and documentation contributions.
November 2024
4 Commits • 1 Features
Nov 1, 2024November 2024: Stabilized Perfetto data flow and visuals through targeted bug fixes, a documentation improvement, and a reliability enhancement in slice handling. Delivered four key items: unknown enum handling in the proto-to-args parser; independent y-axes for battery_stats visualizations; suspend_enter slice termination bug fix via a new state machine; and documentation for update-statsd-descriptor usage. Impact: reduced data type errors, improved visualization accuracy, and more robust slice lifecycle, enabling better performance analysis and faster onboarding. Technologies/skills demonstrated: parser robustness, visualization axis management, state-machine design, code refactoring, and documentation contributions.
October 2024
2 Commits • 2 Features
Oct 1, 2024October 2024 monthly summary for google/perfetto development work. Focused on cleansing the atom registry, improving readability of desktop mode event tracking, and enhancing data visualization in the UI to strengthen observability and debugging capabilities.
2 Commits • 2 Features
Oct 1, 2024October 2024 monthly summary for google/perfetto development work. Focused on cleansing the atom registry, improving readability of desktop mode event tracking, and enhancing data visualization in the UI to strengthen observability and debugging capabilities.
October 2024
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Quality Metrics
Correctness93.0%
Maintainability91.4%
Architecture91.0%
Performance89.2%
AI Usage20.0%
Skills & Technologies
Programming Languages
C++GNJavaScriptMarkdownProtoPythonSQLTextprotoTypeScriptprotobuf
Technical Skills
Android InternalsBuild System ConfigurationBuild SystemsC++C++ DevelopmentCode RefactoringConcurrencyData AnalysisData CollectionData ParsingData ProcessingData SerializationData VisualizationDatabaseDatabase Query Optimization
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