I’m running NASM x86_64 bit assembly on WSL. I’d have expected syscall_vfork to execute processes in parallel, yet it simply runs the parent, then the child.

bits 64
default rel

%include "stringfns.asm" ; basic print functionality

section .data
count: dw 0

section .text
global main

main:
    mov r15, 0
    spawner:
                mov rax, 58
            syscall

        cmp rax, 0
        je child

        call debug ; prints 0n, occurs after child has finished

        inc r15
        cmp r15, 16 
        jne spawner

        jmp exit

    child:
        mov r15, 0
        .loop:
            inc r15
            cmp r15, 1000 ; execute child for some amount of time
            jne .loop   
        inc word [count]

        xor rsi, rsi
        mov si, [count]
        call iprintln ; prints integer in rsi

    exit:
        mov rax, 60
        mov rdi, 0
        syscall

I’ve also set max parallel threads to sixteen, without effect