Boot time slides: mention ltrace too

The description is shared with the embedded Linux course

Signed-off-by: Michael Opdenacker <michael.opdenacker@bootlin.com>

agenda/boot-time-agenda.tex

@@ -174,7 +174,7 @@ \section{Day 2- Morning}
 {Lecture - Application optimization}
 {
   \begin{itemize}
-  \item Using \code{strace}
+  \item Using \code{strace} and \code{ltrace}
   \item Other profiling techniques
   \end{itemize}
 }

agenda/boot-time-fr-agenda.tex

@@ -197,7 +197,7 @@ \section{2\textsuperscript{ème} Jour - Matin}
 {Cours - Optimisation de l'application}
 {
   \begin{itemize}
-  \item Utilisation de \code{strace}
+  \item Utilisation de \code{strace} et \code{ltrace}
   \item Autres techniques de profiling
   \end{itemize}
 }

agenda/boot-time-online-agenda.tex

@@ -169,7 +169,7 @@ \section{Half day 2}
 {Lecture - Application optimization}
 {
   \begin{itemize}
-  \item Using \code{strace}
+  \item Using \code{strace} and \code{ltrace}
   \item Other profiling techniques
   \end{itemize}
 }

agenda/boot-time-online-fr-agenda.tex

@@ -183,7 +183,7 @@ \section{2\textsuperscript{ème} demi-journée}
 {Cours - Optimisation de l'application}
 {
   \begin{itemize}
-  \item Utilisation de \code{strace}
+  \item Utilisation de \code{strace} et \code{ltrace}
   \item Autres techniques de profiling
   \end{itemize}
 }

common/ltrace.tex

@@ -0,0 +1,68 @@
+\begin{frame}
+  \frametitle{ltrace}
+  A tool to trace library calls used by a program and all the signals
+  it receives
+  \begin{itemize}
+  \item Very useful complement to \code{strace}, which shows only system
+    calls. Library calls include system calls too!
+  \item Of course, works even if you don't have the sources
+  \item Allows to filter library calls with regular expressions, or
+    just by a list of function names.
+  \item Manual page: \url{https://linux.die.net/man/1/ltrace}
+  \item Works better with {\em glibc}. \code{ltrace} was broken
+        with {\em uClibc} and may still be.
+  \end{itemize}
+  See \url{https://en.wikipedia.org/wiki/Ltrace} for details
+\end{frame}
+
+\begin{frame}[fragile]
+  \frametitle{ltrace example output}
+  \small
+  \begin{block}{}
+\begin{verbatim}
+ltrace nedit index.html
+sscanf(0x8274af1, 0x8132618, 0x8248640, 0xbfaadfe8, 0) = 1
+sprintf("const 0", "const %d", 0) = 7
+strcmp("startScan", "const 0") = 1
+strcmp("ScanDistance", "const 0") = -1
+strcmp("const 200", "const 0") = 1
+strcmp("$list_dialog_button", "const 0") = -1
+strcmp("$shell_cmd_status", "const 0") = -1
+strcmp("$read_status", "const 0") = -1
+strcmp("$search_end", "const 0") = -1
+strcmp("$string_dialog_button", "const 0") = -1
+strcmp("$rangeset_list", "const 0") = -1
+strcmp("$calltip_ID", "const 0") = -1
+\end{verbatim}
+\end{block}
+\end{frame}
+
+\begin{frame}[fragile]
+  \frametitle{ltrace summary}
+  Example summary at the end of the ltrace output (\code{-c} option)
+  \scriptsize
+  \begin{block}{}
+\begin{verbatim}
+Process 17019 detached
+% time     seconds  usecs/call     calls    errors syscall
+------ ----------- ----------- --------- --------- ----------------
+100.00    0.000050          50         1           set_thread_area
+  0.00    0.000000           0        48           read
+  0.00    0.000000           0        44           write
+  0.00    0.000000           0        80        63 open
+  0.00    0.000000           0        19           close
+  0.00    0.000000           0         1           execve
+  0.00    0.000000           0         2         2 access
+  0.00    0.000000           0         3           brk
+  0.00    0.000000           0         1           munmap
+  0.00    0.000000           0         1           uname
+  0.00    0.000000           0         1           mprotect
+  0.00    0.000000           0        19           mmap2
+  0.00    0.000000           0        50        46 stat64
+  0.00    0.000000           0        18           fstat64
+------ ----------- ----------- --------- --------- ----------------
+100.00    0.000050 288 111 total
+\end{verbatim}
+  \end{block}
+\end{frame}
+

slides/boot-time-application/boot-time-application.tex

@@ -24,6 +24,7 @@ \section{Optimizing applications}
 \end{frame}
 
 \input{../common/strace.tex}
+\input{../common/ltrace.tex}
 
 \begin{frame}
 \frametitle{oprofile}

slides/sysdev-application-development/sysdev-application-development.tex

@@ -494,6 +494,7 @@ \subsection{Memory checkers}
 \subsection{System analysis}
 
 \input{../common/strace.tex}
+\input{../common/ltrace.tex}
 
 \begin{frame}
   \frametitle{ltrace}