I ran the PA in keil and I got bars for various functions showing execution times and percentages.
I could also assign a serial port of a pc as input which is fantastic. I will do that first thing in the morning.
The questions now are as follows:

1. Lots of functions and more interrupt work is done when external input is present like keypress. How can I simulate external key presses? I use a key matrix which makes it impossible to change bits in IO port window! would it have much effect on the program or not coz it only happens when a keypress or discrete event happens ?

2. It gives me time of each individual functions, how can i tell the time of my total loop? do i add each time of a function ?

3. Can i improve overall time if i call the functions that spend too long time once every 1 msec say ?
for example i only scan discrete input every 1 msec or so.