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Zero-Copy I/O and Modern Asynchronous I/O Patterns
Introduction to zero-copy techniques and their impact on system efficiency.
Introduction
In modern backend systems, performance optimization often comes down to reducing unnecessary data copying and context switches. One of the most significant advancements in this area is zero-copy I/O, particularly when combined with asynchronous I/O interfaces. This post explores these concepts in depth, showing how they can dramatically improve application performance.
Understanding Traditional I/O Operations
Before diving into zero-copy operations, let’s understand why traditional I/O operations can be inefficient. Consider a typical proxy server scenario where data needs to be transferred from one socket to another.
Traditional I/O Flow:
1. Application reads data from socket A (kernel → user space copy)
2. Application processes the data (if needed)
3. Application writes data to socket B (user space → kernel copy)
This process involves:
- Multiple context switches between user and kernel mode
- At least two copy operations
- CPU cache pollution
- Additional memory…
