Worked on performance optimization for the facebook/metro repository, focusing on improving worker parallelism and resource utilization. Developed a feature that replaced the use of os.cpus().length with os.availableParallelism() to determine the optimal number of worker threads, enabling Metro to better leverage multi-core hardware. Utilized Node.js runtime APIs and JavaScript to implement and test these changes, with an emphasis on parallel processing and performance profiling. The update reduced processing bottlenecks and improved throughput, particularly under heavy workloads, enhancing scalability for both development and CI environments. No major bugs were addressed during this period, with efforts concentrated on incremental code improvement.