Systemd Boot Optimization dev-mmcblk0p2.device

Question

I'm working on an embedded system and want to make it boot faster.
I already stripped a lot of things. Now I don't know how to improve it further.
Here is my systemd-analyze blame:

4.457s dev-mmcblk0p2.device  
1.303s systemd-journald.service  
 913ms systemd-journal-flush.service  
 793ms systemd-sysctl.service  
 672ms systemd-udev-trigger.service  
 287ms systemd-udevd.service

And here is the systemd-analyze time:

Startup finished in 4.202s (kernel) + 5.179s (userspace) = 9.381s

Does anyone know how to optimize dev-mmcblk0p2.device and/or systemd-journal*.service?

For Information: mmcblk0p2 is an internal emmc where the rootfs is located.

Answer 1

I found out, that I had to modify the kernel commandline in U-boot.
The commandline now Looks like this:

# cat /proc/cmdline 
root=/dev/mmcblk0p2 rootfstype=ext4 rootwait console=ttymxc4,115200 quiet consoleblank=0 coherent_pool=32M