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io_uring (previously known as aioring) is a Linux kernel system call interface for storage device asynchronous I/O operations addressing performance issues with similar interfaces provided by functions like read()/write() or aio_read()/aio_write() etc. for operations on data accessed by file descriptors.[1][2]: 2 

Development is ongoing, worked on primarily by Jens Axboe at Meta.[1]


It works by creating two circular buffers, called "queue rings", for storage of submission and completion of I/O requests, respectively. For storage devices, these are called the submission queue (SQ) and completion queue (CQ).[3] Keeping these buffers shared between the kernel and application helps to boost the I/O performance by eliminating the need to issue extra and expensive system calls to copy these buffers between the two.[1][4][3] According to the io_uring design paper, the SQ buffer is writable only by consumer applications, and the CQ buffer is writable only by the kernel.[1]: 3 


The kernel interface was adopted in Linux kernel version 5.1.[1][4][5] The liburing library provides an API to interact with the kernel interface easily from userspace.[1][1]: 12  The Linux kernel has supported asynchronous I/O since version 2.5, but it was seen as difficult to use and inefficient.[6] This older API only supported certain niche use cases.[7]


  1. ^ a b c d e f g "Linux Kernel Getting io_uring To Deliver Fast & Efficient I/O - Phoronix". Phoronix. Retrieved 2021-03-14.{{cite web}}: CS1 maint: url-status (link)
  2. ^ Axboe, Jens (October 15, 2019). "Efficient IO with io_uring" (PDF).{{cite web}}: CS1 maint: url-status (link)
  3. ^ a b "Getting Hands-on with io_uring using Go". Retrieved 2021-11-20.
  4. ^ a b "The rapid growth of io_uring []". Retrieved 2021-11-20.
  5. ^ "Faster IO through io_uring | Kernel Recipes 2019". Retrieved 2021-03-14.
  6. ^ Corbet, Jonathan. "Ringing in a new asynchronous I/O API". Retrieved 2021-03-14.{{cite web}}: CS1 maint: url-status (link)
  7. ^ "What's new with io_uring" (PDF). Retrieved 2022-06-01.

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