I don't know why linux-kernel@xxxxxxxxxxxxxxx reject my email send out by thunderbird. So here I am resending this mail with git send-email. Here is a test result about DEAD_CODE_DATA_ELIMINATION (DCE) and dead syscalls elimination (DSE). It's based on config[1] and a simple hello.c initramfs. In the DSE test, we set CONFIG_SYSCALLS_USED="sys_write sys_exit sys_reboot," which is used by hello.c to simply print "Hello" then exit and shut down qemu. | | syscall remain | vmlinux size | vmlinux after strip | | ---------------------------------- | -------------- | ---------------- | ------------------- | | disable DCE | 236 | 2559632 | 1963400 | | enable DCE | 208 | 2037384 (-20.4%) | 1485776 (-24.3%) | | enable DCE and DSE(SHE_GROUP) | 3 | 1856640 (-27.6%) | 1354424 (-31.0%) | | enable DCE and DSE(SHE_LINK_ORDER) | 3 | 1856664 (-27.6%) | 1354424 (-31.0%) | It shows that dead syscalls elimination can save 7% of space based on DCE. [1]: https://pastebin.com/KG4fd7aT
