Embedded Resource

Talks

Embedded Linux Size Reduction Techniques

講者:

Michael Opdenacker

Conf:

Embedded Linux Conference 2017

Slides:

http://events.linuxfoundation.org/sites/events/files/slides/opdenacker-embedded-linux-size-reduction-techniques_0.pdf

Video:

https://www.youtube.com/watch?v=ynNLlzOElOU

• 編譯器優化

  • Clang & GCC： -Os

  • Clang： -Oz ，比 -Os 更進一步

• Linker

  • Clang & GCC： -flto

• ARM 平台（ARM mode vs Thumb mode）

  • -marm

  • -mthumb

• Linux kernel

  • make tinyconfig

• BusyBox vs Toybox

  • 相較之下 Toybox 在大小上比較有優勢，而且可以有極小的 rootfs

  • 相較之下 BusyBox 在彈性上比較有優勢，而功能也比較多

• glibc vs uclibc vs musl

• super strip (sstrip)

  • https://github.com/BR903/ELFkickers

  • removes the contents at the end of an ELF file that are not part of the program’s memory image

實測：

$ cat hello.c
#include <stdio.h>

int main() {
    printf("Hello World\n");
}
$ clang hello.c -o hello

$ ll hello
-rwxr-xr-x 1 user user 8312 Mar  3 14:58 hello

$ strip hello
$ ll hello
-rwxr-xr-x 1 user user 6184 Mar  3 14:58 hello

$ sstrip hello
$ ll hello
-rwxr-xr-x 1 user user 4144 Mar  3 14:58 hello