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Linux kernel source tree
checksyscalls.sh is run at every "make" run while building the kernel,
even if no files have changed. I looked at where we spend time in
a trivial empty rebuild and found checksyscalls.sh to be a source
of noticeable overhead, as it spawns a lot of child processes just
to call 'cat' copying from stdin to stdout, once for each of the
over 400 x86 syscalls.
Using a shell-builtin (echo) instead of the external command gives
us a 13x speedup:
Before After
real 0m1.018s real 0m0.077s
user 0m0.068s user 0m0.048s
sys 0m0.156s sys 0m0.024s
The time it took to rebuild a single file on my machine dropped
from 5.5 seconds to 4.5 seconds.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| firmware | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.