mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/
synced 2026-09-28 19:20:30 +00:00
No description
- C 96.9%
- Assembly 0.9%
- Rust 0.6%
- Shell 0.6%
- Python 0.5%
- Other 0.3%
a7bc2e8ddf
In the syscall test of UnixBench, performance regression occurred due
to false sharing.
The lock and atomic members, including file::f_lock, file::f_count and
file::f_pos_lock are highly contended and frequently updated in the
high-concurrency test scenarios. perf c2c indentified one affected
read access, file::f_op.
To prevent false sharing, the layout of file struct is changed as
following
(A) f_lock, f_count and f_pos_lock are put together to share the same
cache line.
(B) The read mostly members, including f_path, f_inode, f_op are put
into a separate cache line.
(C) f_mode is put together with f_count, since they are used frequently
at the same time.
Due to '__randomize_layout' attribute of file struct, the updated layout
only can be effective when CONFIG_RANDSTRUCT_NONE is 'y'.
The optimization has been validated in the syscall test of UnixBench.
performance gain is 30~50%. Furthermore, to confirm the optimization
effectiveness on the other codes path, the results of fsdisk, fsbuffer
and fstime are also shown.
Here are the detailed test results of unixbench.
Command: numactl -C 3-18 ./Run -c 16 syscall fsbuffer fstime fsdisk
Without Patch
------------------------------------------------------------------------
File Copy 1024 bufsize 2000 maxblocks 875052.1 KBps (30.0 s, 2 samples)
File Copy 256 bufsize 500 maxblocks 235484.0 KBps (30.0 s, 2 samples)
File Copy 4096 bufsize 8000 maxblocks 2815153.5 KBps (30.0 s, 2 samples)
System Call Overhead 5772268.3 lps (10.0 s, 7 samples)
System Benchmarks Partial Index BASELINE RESULT INDEX
File Copy 1024 bufsize 2000 maxblocks 3960.0 875052.1 2209.7
File Copy 256 bufsize 500 maxblocks 1655.0 235484.0 1422.9
File Copy 4096 bufsize 8000 maxblocks 5800.0 2815153.5 4853.7
System Call Overhead 15000.0 5772268.3 3848.2
========
System Benchmarks Index Score (Partial Only) 2768.3
With Patch
------------------------------------------------------------------------
File Copy 1024 bufsize 2000 maxblocks 1009977.2 KBps (30.0 s, 2 samples)
File Copy 256 bufsize 500 maxblocks 264765.9 KBps (30.0 s, 2 samples)
File Copy 4096 bufsize 8000 maxblocks 3052236.0 KBps (30.0 s, 2 samples)
System Call Overhead 8237404.4 lps (10.0 s, 7 samples)
System Benchmarks Partial Index BASELINE RESULT INDEX
File Copy 1024 bufsize 2000 maxblocks 3960.0 1009977.2 2550.4
File Copy 256 bufsize 500 maxblocks 1655.0 264765.9 1599.8
File Copy 4096 bufsize 8000 maxblocks 5800.0 3052236.0 5262.5
System Call Overhead 15000.0 8237404.4 5491.6
========
System Benchmarks Index Score (Partial Only) 3295.3
Signed-off-by: chenzhiyin <zhiyin.chen@intel.com>
Message-Id: <20230601092400.27162-1-zhiyin.chen@intel.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
|
History
|
|
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| 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.