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| author | Arnd Bergmann <arnd@arndb.de> | 2017-06-01 16:57:07 +0200 |
|---|---|---|
| committer | Masahiro Yamada <yamada.masahiro@socionext.com> | 2017-06-10 01:15:36 +0900 |
| commit | d21832e212d2613c0a0f3e5f09967cb3402c8a53 (patch) | |
| tree | 7f7264ea38209af59be9d51e80aa67b53f0eec68 /scripts | |
| parent | 6f0fa58e459642b16901521cc58ac474b787ec5b (diff) | |
kbuild: speed up checksyscalls.sh
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>
Diffstat (limited to 'scripts')
| -rwxr-xr-x | scripts/checksyscalls.sh | 11 |
1 files changed, 4 insertions, 7 deletions
diff --git a/scripts/checksyscalls.sh b/scripts/checksyscalls.sh index 116b7735ee9f..5a387a264201 100755 --- a/scripts/checksyscalls.sh +++ b/scripts/checksyscalls.sh @@ -202,15 +202,12 @@ EOF } syscall_list() { - grep '^[0-9]' "$1" | sort -n | ( + grep '^[0-9]' "$1" | sort -n | while read nr abi name entry ; do - cat <<EOF -#if !defined(__NR_${name}) && !defined(__IGNORE_${name}) -#warning syscall ${name} not implemented -#endif -EOF + echo "#if !defined(__NR_${name}) && !defined(__IGNORE_${name})" + echo "#warning syscall ${name} not implemented" + echo "#endif" done - ) } (ignore_list && syscall_list $(dirname $0)/../arch/x86/entry/syscalls/syscall_32.tbl) | \ |