3d8ef251aa
When the buffer is immediately preceeded by the character we are looking for and begins with one higher than that character, and the buffer is misaligned, a match was errorneously detected in the first character. Fix this by changing the way we prevent matches before the buffer from being detected: instead of removing the corresponding bit from the 0x80..80 mask, set the LSB of bytes before the buffer after xoring with the character we look for. The bug only affects amd64 with ARCHLEVEL=scalar (cf. simd(7)). The change comes at a 2% performance impact for short strings if ARCHLEVEL is set to scalar. The default configuration is not affected. os: FreeBSD arch: amd64 cpu: 11th Gen Intel(R) Core(TM) i7-1165G7 @ 2.80GHz │ strchrnul.scalar.0.out │ strchrnul.scalar.2.out │ │ sec/op │ sec/op vs base │ Short 57.89µ ± 2% 59.08µ ± 1% +2.07% (p=0.030 n=20) Mid 19.24µ ± 0% 19.73µ ± 0% +2.53% (p=0.000 n=20) Long 11.03µ ± 0% 11.03µ ± 0% ~ (p=0.547 n=20) geomean 23.07µ 23.43µ +1.53% │ strchrnul.scalar.0.out │ strchrnul.scalar.2.out │ │ B/s │ B/s vs base │ Short 2.011Gi ± 2% 1.970Gi ± 1% -2.02% (p=0.030 n=20) Mid 6.049Gi ± 0% 5.900Gi ± 0% -2.47% (p=0.000 n=20) Long 10.56Gi ± 0% 10.56Gi ± 0% ~ (p=0.547 n=20) geomean 5.045Gi 4.969Gi -1.50% MFC to: stable/14 MFC after: 3 days Approved by: mjg (blanket, via IRC) Sponsored by: The FreeBSD Foundation |
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.cirrus-ci | ||
.github | ||
bin | ||
cddl | ||
contrib | ||
crypto | ||
etc | ||
gnu | ||
include | ||
kerberos5 | ||
lib | ||
libexec | ||
release | ||
rescue | ||
sbin | ||
secure | ||
share | ||
stand | ||
sys | ||
targets | ||
tests | ||
tools | ||
usr.bin | ||
usr.sbin | ||
.arcconfig | ||
.arclint | ||
.cirrus.yml | ||
.clang-format | ||
.git-blame-ignore-revs | ||
.gitattributes | ||
.gitignore | ||
CONTRIBUTING.md | ||
COPYRIGHT | ||
LOCKS | ||
MAINTAINERS | ||
Makefile | ||
Makefile.inc1 | ||
Makefile.libcompat | ||
Makefile.sys.inc | ||
ObsoleteFiles.inc | ||
README.md | ||
RELNOTES | ||
UPDATING |
FreeBSD Source:
This is the top level of the FreeBSD source directory.
FreeBSD is an operating system used to power modern servers, desktops, and embedded platforms. A large community has continually developed it for more than thirty years. Its advanced networking, security, and storage features have made FreeBSD the platform of choice for many of the busiest web sites and most pervasive embedded networking and storage devices.
For copyright information, please see the file COPYRIGHT in this directory. Additional copyright information also exists for some sources in this tree - please see the specific source directories for more information.
The Makefile in this directory supports a number of targets for building components (or all) of the FreeBSD source tree. See build(7), config(8), FreeBSD handbook on building userland, and Handbook for kernels for more information, including setting make(1) variables.
For information on the CPU architectures and platforms supported by FreeBSD, see the FreeBSD website's Platforms page.
Source Roadmap:
Directory | Description |
---|---|
bin | System/user commands. |
cddl | Various commands and libraries under the Common Development and Distribution License. |
contrib | Packages contributed by 3rd parties. |
crypto | Cryptography stuff (see crypto/README). |
etc | Template files for /etc. |
gnu | Commands and libraries under the GNU General Public License (GPL) or Lesser General Public License (LGPL). Please see gnu/COPYING and gnu/COPYING.LIB for more information. |
include | System include files. |
kerberos5 | Kerberos5 (Heimdal) package. |
lib | System libraries. |
libexec | System daemons. |
release | Release building Makefile & associated tools. |
rescue | Build system for statically linked /rescue utilities. |
sbin | System commands. |
secure | Cryptographic libraries and commands. |
share | Shared resources. |
stand | Boot loader sources. |
sys | Kernel sources (see sys/README.md). |
targets | Support for experimental DIRDEPS_BUILD |
tests | Regression tests which can be run by Kyua. See tests/README for additional information. |
tools | Utilities for regression testing and miscellaneous tasks. |
usr.bin | User commands. |
usr.sbin | System administration commands. |
For information on synchronizing your source tree with one or more of the FreeBSD Project's development branches, please see FreeBSD Handbook.