7cdaf587de
If requests can be submitted and completed inline, we don't need to initialize whole io_wq_work in io_init_req(), which is an expensive operation, add a new 'REQ_F_WORK_INITIALIZED' to determine whether io_wq_work is initialized and add a helper io_req_init_async(), users must call io_req_init_async() for the first time touching any members of io_wq_work. I use /dev/nullb0 to evaluate performance improvement in my physical machine: modprobe null_blk nr_devices=1 completion_nsec=0 sudo taskset -c 60 fio -name=fiotest -filename=/dev/nullb0 -iodepth=128 -thread -rw=read -ioengine=io_uring -direct=1 -bs=4k -size=100G -numjobs=1 -time_based -runtime=120 before this patch: Run status group 0 (all jobs): READ: bw=724MiB/s (759MB/s), 724MiB/s-724MiB/s (759MB/s-759MB/s), io=84.8GiB (91.1GB), run=120001-120001msec With this patch: Run status group 0 (all jobs): READ: bw=761MiB/s (798MB/s), 761MiB/s-761MiB/s (798MB/s-798MB/s), io=89.2GiB (95.8GB), run=120001-120001msec About 5% improvement. Signed-off-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> |
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|---|---|---|
| Documentation | ||
| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
README
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.