My application speed is low when run at linux startup - linux

Question

I have an embedded console application created with Qt,C++. I use nanopi fire (FriendlyARM) for my device with Linux arch. I connect it's gpio as relay for turning on and off the lamps of my room. Also I wrote mobile app to connect the device with socket. When I run my program from putty ./SmartKeyC it runs and I can switch the lamps with my mobile app buttons and all of them are ok.
But when I put my program on start up for auto run, all of functions do their tasks with 2-3 seconds delay.
I used this link to create auto run app. this is my script:
#! /bin/sh
### BEGIN INIT INFO
# Provides: <your script name>
# Required-Start: $all
# Required-Stop:
# Default-Start: 2 3 4 5
# Default-Stop: 0 1 6
# Short-Description: Manage my cool stuff
### END INIT INFO
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/opt/bin:/root
. /lib/init/vars.sh
. /lib/lsb/init-functions
. /root/
# If you need to source some other scripts, do it here
case "$1" in
start)
log_begin_msg "Starting my super cool service"
# do something
/root/SmartKeyC
log_end_msg $?
exit 0
;;
stop)
log_begin_msg "Stopping the coolest service ever unfortunately"
# do something to kill the service or cleanup or nothing
log_end_msg $?
exit 0
;;
*)
echo "Usage: /etc/init.d/<your script> {start|stop}"
exit 1
;;
esac
and after update rc I have:
root#NanoPi2-Fire:/etc# find -iname "*SmartKeyScript"
./init.d/SmartKeyScript
./rc0.d/K01SmartKeyScript
./rc1.d/K01SmartKeyScript
./rc2.d/S03SmartKeyScript
./rc3.d/S03SmartKeyScript
./rc4.d/S03SmartKeyScript
./rc5.d/S03SmartKeyScript
./rc6.d/K01SmartKeyScript
Where is the problem?
Why when I run my app in putty , everything works good , but when my app starts from auto run it has delay for each function calling?

Answer 1

I remove my script from rcX and put file in my rc.local like below:
Vi /etc/rc.local
#!/bin/sh -e
#
# rc.local
#
# This script is executed at the end of each multiuser runlevel.
# Make sure that the script will "exit 0" on success or any other
# value on error.
#
# In order to enable or disable this script just change the execution
# bits.
#
# By default this script does nothing.
/usr/local/bin/gen-friendlyelec-release
. /etc/friendlyelec-release
if [ ! -f /etc/firstuse ]; then
/bin/echo ${BOARD} > /etc/hostname
/bin/sed -i "s/\(127.0.1.1\s*\).*/\1${BOARD}/g" /etc/hosts
/bin/hostname ${BOARD}
/bin/echo "0" > /etc/firstuse
fi
. /usr/bin/setqt5env
/usr/bin/lcd2usb_print "CPU: {{CPU}}" "Mem: {{MEM}}" "IP: {{IP}}" "LoadAvg: {{LOADAVG}}" 2>&1 > /dev/null&
#/opt/QtE-Demo/run.sh&
/root/SmartKeyC & > /dev/tty0
exit 0