Originally published on tamiz.pro.
Introduction
In high-performance Go applications, traditional I/O operations often introduce unnecessary data copies between kernel and user space. This article explores zero-copy techniques like sendfile, splice, and the hidden costs of io.Copy, providing actionable insights for optimizing throughput and reducing CPU overhead in network services, file servers, and data pipelines.
Understanding Zero-Copy I/O
Zero-copy eliminates redundant memory copies during data transfer by leveraging kernel-level optimizations. Traditional I/O operations involve three memory copies (disk→kernel→user→network) and multiple context switches, while zero-copy solutions reduce this to a single copy (disk→network) when possible. This is critical for applications handling terabytes of data daily, such as CDN servers, stream processors, and large-scale APIs.
