Skip to content

Zero-copy I/O optimization

Zero-copy I/O refers to optimization techniques designed to reduce the number of data copies and context switches between the operating system kernel and user space during data transfer.^[600-developer__java__java-io__java-socket.md]

Context and Motivation

In standard file-to-network transmission (e.g., reading a file and sending it over a socket), traditional I/O operations often involve multiple data copies and context switches between kernel mode and user mode^[600-developer__java__java-io__java-socket.md]. These operations introduce CPU overhead and memory bandwidth consumption, which can become bottlenecks in high-throughput applications.

Comparison with Traditional I/O

Visual comparisons often illustrate the data flow differences:

  • Traditional I/O (BIO): Typically involves reading data from disk to kernel space, copying to user space, and then copying back to kernel space for transmission^[600-developer__java__java-io__java-socket.md].
  • Zero-copy I/O: Optimized paths allow data to be transferred directly from the disk file system to the network interface card (NIC), bypassing unnecessary copies through user space buffers^[600-developer__java__java-io__java-socket.md].
  • [[Java NIO]]
  • I/O Models (Select, Epoll)
  • [[Context Switch]]

Sources

  • 600-developer__java__java-io__java-socket.md^[600-developer__java__java-io__java-socket.md]