Worked on core PHP performance optimization within the php/php-src repository, focusing on improving callback function efficiency. Developed and delivered a feature that introduced consumed_args support for function call arguments, targeting reduced memory overhead during callback invocations. This technical approach enhanced the performance of array_reduce and other callback-driven functions, resulting in better throughput and lower latency for applications with heavy callback usage. The optimization also contributed to decreased garbage collection pressure in high-load scenarios. Utilized C programming and deep knowledge of PHP internals to implement these changes, emphasizing performance optimization as a primary goal throughout the development process during the project period.