improved the report pdf

LaTeX/Homework_Lesson_10.tex

@@ -32,6 +32,71 @@ Submit the source code and the screen shots of the standard output and the kerne
 \section{Code}%
 \label{sec:Code}
 
+\subsection{Custom Python Code}%
+\label{sub:Custom Python Code}
+The following code was written by me with the intend to measure the jitter in a python code.
+It uses the \textit{schedtool} program provided with the PREEMPT\_RT patches to schedule itself.
+\definecolor{mGreen}{rgb}{0,0.6,0}
+\definecolor{mGray}{rgb}{0.5,0.5,0.5}
+\definecolor{mPurple}{rgb}{0.58,0,0.82}
+\definecolor{backgroundColour}{rgb}{0.95,0.95,0.92}
+\lstset{
+    language=python,
+    backgroundcolor=\color{backgroundColour},   
+    commentstyle=\color{mGreen},
+    keywordstyle=\color{magenta},
+    numberstyle=\tiny\color{mGray},
+    stringstyle=\color{mPurple},
+    basicstyle=\ttfamily\scriptsize,
+    breakatwhitespace=false,         
+    breaklines=true,                 
+    captionpos=b,                    
+    keepspaces=true,                 
+    numbers=left,                    
+    firstnumber=0,
+    stepnumber=1,
+    numbersep=5pt,                  
+    showspaces=false,                
+    showstringspaces=false,
+    showtabs=false,                  
+    tabsize=2,
+    literate={~}{{$\mathtt{\sim}$}}1
+}
+\lstset{literate=%
+    {Ö}{{\"O}}1
+    {Ä}{{\"A}}1
+    {Ü}{{\"U}}1
+    {ß}{{\ss}}2
+    {ü}{{\"u}}1
+    {ä}{{\"a}}1
+    {ö}{{\"o}}1
+}
+\lstinputlisting{../test.py}
+\clearpage
+
+\subsubsection{Output}%
+\label{ssub:Python:Output}
+Unfortunately, as can be seen by the following output,
+the jitter isn't really affected by the activation or deactivation of the PREEMPT\_RT patches.
+
+\paragraph{with PREEMPT\_RT}%
+\label{par:Python:with PREEMPT RT}
+\begin{center}
+    \includegraphics[width = .75\textwidth]{with_preempt_rt.png}
+\end{center}
+
+\paragraph{without PREEMPT\_RT}%
+\label{par:Python:without PREEMPT RT}
+\begin{center}
+    \includegraphics[width = .75\textwidth]{no_preempt_rt.png}
+\end{center}
+\clearpage
+
+\subsection{Using Existing Programs}%
+\label{sub:Using Existing Programs}
+The following code is just a shell script that makes use of two programs provided by the \texttt{rt-tests} package (Arch Linux).
+It uses the \texttt{hackbench} program to put stress on the system and then evaluates the maximum latency with the \texttt{cyclictest} program.
+This provides a much more reliable method of testing the real-time capabilites of the system than any self-developed code I was able to come up with.
 \definecolor{mGreen}{rgb}{0,0.6,0}
 \definecolor{mGray}{rgb}{0.5,0.5,0.5}
 \definecolor{mPurple}{rgb}{0.58,0,0.82}
@@ -67,24 +132,23 @@ Submit the source code and the screen shots of the standard output and the kerne
     {ä}{{\"a}}1
     {ö}{{\"o}}1
 }
-
-The following code is just a shell script that makes use of two programs provided by the \texttt{rt-tests} package (Arch Linux).
-It uses the \texttt{hackbench} program to put stress on the system and then evaluates the maximum latency with the \texttt{cyclictest} program.
-This provides a much more reliable method of testing the real-time capabilites of the system than any self-developed code I was able to come up with.
 \lstinputlisting{../test.sh}
 The code is based on the following two sources:\\
 \url{https://wiki.archlinux.org/title/Realtime_kernel_patchset}\\
 \url{https://shuhaowu.com/blog/2022/02-linux-rt-appdev-part2.html}
 
-\section{Output}%
+\subsubsection{Output}%
-\label{sec:Output}
+\label{ssub:BASH:Output}
+The following output shows that while the PREEMPT\_RT patch doesn't really affect the average latency it drastically reduces the maximum latency.
 
-\subsection{with PREEMPT\_RT}%
+\paragraph{with PREEMPT\_RT}%
-\label{sub:with PREEMPT RT}
+\label{par:BASH:with PREEMPT RT}
+\mbox{}\\
 \includegraphics[width = \textwidth]{with_rt.png}
 
-\subsection{without PREEMPT\_RT}%
+\paragraph{without PREEMPT\_RT}%
-\label{sub:without PREEMPT RT}
+\label{par:BASH:without PREEMPT RT}
+\mbox{}\\
 \includegraphics[width = \textwidth]{without_rt.png}
 
 \end{document}

test.py

@@ -0,0 +1,44 @@
+import subprocess
+import time
+import matplotlib.pyplot as plt
+
+ITERATIONS = 300
+ITERATION_DURATION = 1 #second(s)
+
+def set_rt_priority():
+   subprocess.run(["schedtool", "-F", "-p", "99"], check=True)
+
+def rt_task():
+    new_time = time.time()
+    jitter_record = []
+
+    for i in range(ITERATIONS + 1):
+        old_time = new_time
+        new_time = time.time()
+
+        print("--------------------------------------------------")
+        print(f"system time:\t{new_time} s")
+        print(f"time diff:\t{new_time - old_time} s")
+
+        # jitter
+        jitter = new_time - old_time - ITERATION_DURATION
+        jitter_record.append(jitter)
+        print(f"jitter:\t{jitter} s")
+
+        # sleep for the rest of one second
+        time.sleep(new_time + ITERATION_DURATION - time.time())
+
+    #remove the first measurement
+    jitter_record.pop(0) 
+
+    #plot and store the jitter record
+    plt.plot(jitter_record)
+    plt.title(f"Jitter at {ITERATION_DURATION} s interval")
+    plt.xlabel("Iteration")
+    plt.ylabel("Jitter (in s)")
+    plt.savefig("out.svg")
+
+
+if __name__ == "__main__":
+    set_rt_priority()
+    rt_task()