Common Backend Impl (CBI)

The common backend implementations are implementations for re-use by other platforms. For example, instead of the Linux, FreeBSD, and macOS platforms all implementing the same POSIX asynchronous I/O interface, it is instead provided here, and they can all include it in their backend configs.

Similarly, xNVMe provides several software-only implementations of the xNVMe API, such as the thrpool which implements the asynchronous parts of the xNVMe API by using a thread-pool.

Each platform composes these CBI components into predefined backend configs (xnvme_be_config), providing tested and validated combinations. In addition to common implementations and interface emulation, xNVMe also provides simple device emulation via the ramdisk backend implementation.

Instrumentation

• Memory Allocators

  • posix, Use libc malloc()/free() with sysconf() for alignment, add link to CBI

• Asynchronous Interfaces

  • nil, xNVMe null-IO, does nothing but complete submitted commands, for experimentation only to evaluate xNVMe encapsulation overhead

  • emu, ..

  • thrpool, ..

  • posix, ..

• Synchronous Interfaces

  • psync, Use pread()/write() for synchronous I/O