path: root/scripts
diff options
authorArnd Bergmann <arnd@arndb.de>2017-06-01 16:57:07 +0200
committerMasahiro Yamada <yamada.masahiro@socionext.com>2017-06-10 01:15:36 +0900
commitd21832e212d2613c0a0f3e5f09967cb3402c8a53 (patch)
tree7f7264ea38209af59be9d51e80aa67b53f0eec68 /scripts
parent6f0fa58e459642b16901521cc58ac474b787ec5b (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')
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 ${name} not implemented
+ echo "#if !defined(__NR_${name}) && !defined(__IGNORE_${name})"
+ echo "#warning syscall ${name} not implemented"
+ echo "#endif"
- )
(ignore_list && syscall_list $(dirname $0)/../arch/x86/entry/syscalls/syscall_32.tbl) | \