Algorithm effect on the CPU

[Faruk]

Hello guys. I have a python 2.7 script for my raspberry pi. My problem is When I run code, Raspberry pi use %20 of CPU. I think, wrong something in my code. I saw else program bigger than mine(Also it runs video and render image) but it use %5 of CPU. I think my algorithm is wrong but I couldn't find any solution. My code this. If you can helping to me, I will happy. Thanks your time.

Program details is: Rpi connect with uart to stm. Stm transmit data to Rpi. Rpi read incoming data and it shows on the GUI. Also there is image on GUI. My python program runs for Rpi.

#! /usr/bin/python
# -*-coding: utf-8 -*-


#-Library setting-#
import RPi.GPIO as gpio
import time
import serial
from Tkinter import *
from ttk import Frame, Style, Button
from PIL import ImageTk, Image

import subprocess
from playsound import playsound




gpio.setmode(gpio.BCM)
gpio.setwarnings(False)
gpio.setup(33, gpio.IN)


#-Buffer definition-#
dataarray=''
data=''
uartData=''
dstflg=False
dspflg=False
dataflg=False
testflg=False
floorinfoflg=False
control_count=0


#-Serial port config-#
try:
    stmSer=serial.Serial(port='/dev/ttyAMA0', baudrate=115200,
                  parity=serial.PARITY_NONE,
                  stopbits=serial.STOPBITS_ONE,
                  bytesize=serial.EIGHTBITS,
				  timeout=0.00001     
                  )
except serial.SerialException:
    import traceback
    traceback.print_exc()
    print "Stmser except error"
    L1=Label(root, text=(traceback.print_exc()))
    L1.place(x=10, y=400)
    
    


#-GUI update according to data of 'CARSTAT'-#
def updateGUI(data):
    global left_character
    global right_character
    global call_up
    global call_down
    global travel_up
    global travel_down
    global floorinfoflg
    global control


    try:
        left_character=(data[10:12]).decode("hex")
        right_character=(data[12:14]).decode("hex")

        petra_status_1=format(ord(data[14:16].decode("hex")),'08b')

        print "UpdateGUI"
        
        travel_down=petra_status_1[4]
        travel_up=petra_status_1[3]

        katno.config(text=left_character+right_character, font=("Arial", 300))
        
        print "UpdaaeGUI work"
        
        if travel_up=="1":
            image=Image.open("/home/pi/Petra/upArrow2.png")
            photo=ImageTk.PhotoImage(image)
            label.config(image=photo)
            label.photo_ref=photo

            if left_character=="1" or left_character=="2":
                katno.config(text=left_character+right_character, font=("Arial", 210))
                katno.place(x=0,y=40)
            else:
                katno.config(text=left_character+right_character, font=("Arial", 300))
                katno.place(x=-90,y=-30)
        elif travel_down=="1":
            image=Image.open("/home/pi/Petra/downArrow2.png")
            photo=ImageTk.PhotoImage(image)
            label.config(image=photo)
            label.photo_ref=photo
            
            if left_character=="1" or left_character=="2":
                katno.config(text=left_character+right_character, font=("Arial", 210))
                katno.place(x=0,y=40)
            else:
                katno.config(text=left_character+right_character, font=("Arial", 300))
                katno.place(x=-90,y=-30)
        elif travel_up=="0" and travel_down=="0":
            image=Image.open("/home/pi/Petra/upArrow2.png")
            photo=ImageTk.PhotoImage(image)
            label.config(image='')
            label.photo_ref=photo
            if left_character=="0":
                katno.config(text=left_character+right_character, font=("Arial", 300))
                katno.place(x=-150, y=-30)
            elif left_character=="1" or left_character=="2":
                katno.config(text=left_character+right_character, font=("Arial", 300))
                katno.place(x=-150, y=-30)
            else:
                katno.config(text=left_character+right_character, font=("Arial", 300))
                katno.place(x=-190, y=-30)
        else:
            print "travel conditions ERROR"

        
        root.after(15,loop)
    except:
        import traceback
        traceback.print_exc()
        print "UpdateGUI Error"
        prgloop()
        L2=Label(root, text=(traceback.print_exc()))
        L2.place(x=10, y=400)
        
    

    
###-Data Read -#
def readuart():
    global dataread
    global datalist
    global dataarray
    global dstflg
    global dspflg
    global testflg
    global stmSer
    
    while True:
        try:
            if stmSer.inWaiting()>0:
                dataread=stmSer.read(1)

                if testflg==True:
                    dstflg=True
                    dspflg=True
                
                if dataread=='@' and dstflg==False:
                   dstflg=True
                   dspflg=False
                   dataarray=''
                elif dataread=='$' and dspflg==False:
                    dspflg=True
                    dstflg=False
                    #print "dataarray: "+dataarray
                    
                    return dataarray
                    dataarray=''
                else:
                    if dstflg==True and dspflg==False:
                        dataarray=dataarray+''.join(dataread)
                    elif dstflg==True and dspflg==True:
                        print "Reset loop"
                        dataarray=''
                        uartData=''
                        writeda=''
                        testflg=False
                        dstflg=False
                        dspflg=False
                        root.after(5,readuart)
                        
                    elif dstflg==False and dspflg==False:
                        print "Reset loop"
                        dataarray=''
                        uartData=''
                        writeda=''
                        testflg=False
                        dstflg=False
                        dspflg=False
                        root.after(5,readuart)
                        
                    else:
                        print "ERROR!!"
                        
                    input_value = gpio.input(33)    ##Button Pgm_DW
                    if input_value == True:
                        testflg=True
                        dataarray=''
                        uartData=''
                        writeda=''
                        #print('The button has been pressed...')
            #else:
                #print "Data bekleniyor."
        except:
            import traceback
            traceback.print_exc()
            print "readUart Error"
            L3=Label(root, text=(traceback.print_exc()))
            L3.place(x=10, y=400)
            print "readUart Error"
            

def prgloop():
    print "Reset prgloop"
    testflg=False
    root.after(5,loop)

def render():
    image2=Image.open('/home/pi/Petra/image_new.jpg')
    photo2=ImageTk.PhotoImage(image2)
    label2=Label(image=photo2, bg="#142F5E")
    label2.image=photo2
    label2.config(height=375, width=480)
    label2.place(x=0, y=430)
    

    
#-Furcation to update function  -#
def loop():
    global dataread
    global datalist
    global dataarray
    global dstflg
    global uartData
    global dspflg
    global data

    dspflg=False

    try:
        uartData=readuart() 
    
    
        if uartData[:8]=='CARSTAT,':
            updateGUI(uartData)
            #print "data: "+uartData
        else:
            #print "İnvalid Data"
            root.after(5,loop)
    
            
    except:
        print "Update ERROR"
        import traceback
        traceback.print_exc()
        L4=Label(root, text=(traceback.print_exc()))
        L4.place(x=10, y=400)
        prgloop()
    
    

#-Graphical Design-#
    
try:
    root=Tk()
    root.title('V0.8')
    root.overrideredirect(0)

    
    

    katno=Label(root, text='1', font=("Arial", 300), width=2, fg='white', bg='#2080FF')
    katno.place(x=-90, y=-40)
    katno.config(padx=170)
    

    image=Image.open('/home/pi/Petra/upArrow2.png')
    photo=ImageTk.PhotoImage(image)
    label=Label(image=photo, bg="#2080FF")
    label.image=photo
    label.place(x=30, y=50)

        
    root.configure(background="#2080FF")
    root.geometry('480x400+0+0')
    
    render()
    loop()
    root.mainloop()
except:
    import traceback
    traceback.print_exc()
    L5=Label(root, text=(traceback.print_exc()))
    L5.place(x=10, y=40)
    print "GUI ERROR"

[Larz60+]

One thing that stands out is that your timeout is very short.
Making it longer is OK, the port will not wait for timeout after data has been transferred, it's a maximum value.

[jeanMichelBain]

Hello, some thought
I believe too things are imbricated in your program.
1 - It does loop and then after(5,loop), which stack again your loop into the system, probably increasing the stack, which is wrong.
2 - In "loop()", an "except: prgloop()" which does the same "after(5,loop)". If an exception occurs, it will stacked, and if a new one occurs, you will reach eventually the python exception stack limit. Not very important because you will be notified.
3 - If I'm good, "after(5,loop)" means you start the loop again after 5ms. It's very few, and it could be the reason of your cpu time waste. I don't know Tk, but in the GUI I know, I never do that because... it does use a lot of CPU for nothing. The purpose of a GUI system is to react after a GUI event, not to process some other system, like for instance a serial device. Anyway, you stack a new loop every 5ms, and this is wrong. You can get a proof of that if the free memory of your system decreases regularly (try htop utility on your RPI, in the standard repository). If it does not, I'm wrong, but I'm sure it cannot be a good practice.
What you can do is :
- change your code to make the GUI starting events as it wants and terminate the event processing as quickly as possible, and don't start something long at the end of this event process.
- process the serial line in another thread, which will live alone and won't use too much the CPU. There are excellent threading modules coming with python ; choose one compatible with Tk. Does somebody has any hint about that ?. You can look and post in the GUI forum.
- If you don't have any other solution, increase the 5ms (try for instance 20ms). You can also try the time module (ex: time.sleep(0.2)) which is good to give your system some breath.

[Faruk]

Thanks for your reply