This patch series adds support for the newly developed io_uring Linux AIO interface. Linux io_uring is faster than Linux's AIO asynchronous I/O code, offers efficient buffered asynchronous I/O support, the ability to do I/O without performing a system call via polled I/O, and other efficiency enhancements.
Testing it requires a host kernel (5.1+) and the liburing library. Use the option -drive aio=io_uring to enable it. Benchmarks for the system at https://github.com/rooshm/benchmarks io_uring has similar performance as libaio but supports cache=writeback. Further performance enhancement will be implemented There is currently an -EIO output when guests are booted from io_uring on ext4, the error is reported upstream. https://lore.kernel.org/linux-block/20190723080701.GA3198@stefanha-x1.localdomain/ v8: - adds fd_registration v7: - completes io-tests options - misc fixes v6: - add slow path for short-read - hooks up fsync - enables qemu-iotests with aio options - adds bdrv_parse_aio v5: - Adds completion polling - Extends qemu-io - Adds qemu-iotest v4: - Add error handling - Add trace events - Remove aio submission based code Aarushi Mehta (16): configure: permit use of io_uring qapi/block-core: add option for io_uring block/block: add BDRV flag for io_uring block/io_uring: implements interfaces for io_uring stubs: add stubs for io_uring interface util/async: add aio interfaces for io_uring blockdev: adds bdrv_parse_aio to use io_uring block/file-posix.c: extend to use io_uring block: add trace events for io_uring block/io_uring: adds userspace completion polling qemu-io: adds option to use aio engine qemu-img: adds option to use aio engine for benchmarking qemu-nbd: adds option for aio engines tests/qemu-iotests: enable testing with aio options tests/qemu-iotests: use AIOMODE with various tests block/io_uring: adds fd registration MAINTAINERS | 8 + block.c | 22 ++ block/Makefile.objs | 3 + block/file-posix.c | 99 +++++-- block/io_uring.c | 522 ++++++++++++++++++++++++++++++++++ block/trace-events | 13 + blockdev.c | 12 +- configure | 27 ++ include/block/aio.h | 16 +- include/block/block.h | 2 + include/block/raw-aio.h | 12 + qapi/block-core.json | 4 +- qemu-img-cmds.hx | 2 +- qemu-img.c | 11 +- qemu-img.texi | 5 +- qemu-io.c | 25 +- qemu-nbd.c | 12 +- qemu-nbd.texi | 4 +- stubs/Makefile.objs | 1 + stubs/io_uring.c | 32 +++ tests/qemu-iotests/028 | 3 +- tests/qemu-iotests/058 | 2 +- tests/qemu-iotests/089 | 4 +- tests/qemu-iotests/091 | 7 +- tests/qemu-iotests/109 | 3 +- tests/qemu-iotests/147 | 5 +- tests/qemu-iotests/181 | 10 +- tests/qemu-iotests/183 | 7 +- tests/qemu-iotests/185 | 17 +- tests/qemu-iotests/200 | 3 +- tests/qemu-iotests/201 | 10 +- tests/qemu-iotests/check | 15 +- tests/qemu-iotests/common.rc | 14 + tests/qemu-iotests/iotests.py | 9 +- util/async.c | 36 +++ 35 files changed, 899 insertions(+), 78 deletions(-) create mode 100644 block/io_uring.c create mode 100644 stubs/io_uring.c -- 2.21.0
