Developed a performance-focused Speculative Decoding Input Preprocessing Kernel for the PaddlePaddle/FastDeploy repository, targeting improved efficiency in token handling during speculative decoding. The work involved designing and implementing the kernel using CUDA and C++, with careful attention to concurrency by resolving multithreading race conditions. Asynchronous device-to-host data transfer was introduced to optimize throughput, and preprocessing was streamlined by eliminating redundant data slices, reducing memory usage. The codebase was refactored for clarity and maintainability, and comprehensive unit tests were added to ensure reliability. All changes were aligned with the target pull request, demonstrating a methodical approach to GPU programming and unit testing.