BAD smell: empty infinite loop

ome people like to use empty infinite loop to implement the “waiting“. It is a BAD design because this design will block your CPU !!! I make a practice to explain this situation.
Examples of empty infinite loop:
while(condition_flap == true){
​
}
for(;;){
}
My test: busy.c
int main(){
for(;;){
}
}
Compile:
$ gcc busy.c -o busy
Execute:
./busy
CPU usage:
$ ps -eo pid,ppid,cmd,%mem,%cpu --sort=-%cpu | head
PID PPID CMD %MEM %CPU
13775 8550 ./busy 0.0 99.0
31292 29618 /snap/code/33/usr/share/cod 5.6 1.7
21935 21893 /snap/code/32/usr/share/cod 0.1 0.6
7264 1 /usr/lib/firefox/firefox -n 2.7 0.4
29654 29618 /snap/code/33/usr/share/cod 0.4 0.4
31331 31292 /snap/code/33/usr/share/cod 0.1 0.4
7408 7264 /usr/lib/firefox/firefox -c 1.2 0.3
1224 31316 /usr/lib/jvm/java-8-openjdk 4.8 0.2
7426 7264 /usr/lib/firefox/firefox -c 1.1 0.2
Assembly:
$ gcc -S busy.c -o busy.s; more busy.s
.file "busy.c"
.text
.globl main
.type main, @function
main:
.LFB0:
.cfi_startproc
pushq %rbp
.cfi_def_cfa_offset 16
.cfi_offset 6, -16
movq %rsp, %rbp
.cfi_def_cfa_register 6
.L2:
jmp .L2
.cfi_endproc
.LFE0:
.size main, .-main
.ident "GCC: (Ubuntu 7.5.0-3ubuntu1~18.04) 7.5.0"
.section .note.GNU-stack,"",@progbits
Conclusion: DON’T use empty infinity to be your waiting timer. Ref. 讓CPU瞎忙的忙碌迴圈 Why does an empty infinite loop use my whole CPU?​