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Added section about profiling

git-svn-id: file:///Users/olsen/Code/migration-svn-zu-git/logical-line-staging/clib2/trunk@14982 87f5fb63-7c3d-0410-a384-fd976d0f7a62
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Thomas Frieden
2005-06-15 15:23:29 +00:00
parent 196ce6e140
commit f81dfdfca7

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@ -172,7 +172,34 @@ file descriptors <tt>STDIN_FILENO</tt>/<tt>STDOUT_FILENO</tt>/<tt>STDERR_FILENO<
It is therefore strongly recommended to use the thread-safe library only for applications It is therefore strongly recommended to use the thread-safe library only for applications
which can cope with the limitations described above.</p> which can cope with the limitations described above.</p>
<h3>5.3 Using gmon (PowerPC only)</h3>
<p>To use profiling, two steps are required. First of all, your program must be compiled with
the gcc command line option <tt>-pg</tt>. This instructs the compiler to generate special
profiling code in the prologue and epilogue of each function. Additionally, the program
must be linked with <tt>libprofile.a</tt>. To do this, either manually add
<tt>-lprofile</tt> to the linker command line, or modify the specs file as follows.
Find the lines that look like this (it may actually differ silghtily from your specs file,
but the important thing is that the line before the line to be modified reads <tt>lib:</tt>):
<pre>
lib:
--start-group -lc --end-group
</pre>
You will have to modify this to look like this:
<pre>
lib:
%{pg: -lprofile} --start-group -lc --end-group
</pre>
Normally, the specs file is located at the compilers installation directory. For cross-compilers,
this is <tt>/usr/local/amiga/lib/gcc/ppc-amigaos/<i>compiler-version</i>/specs</tt>. For a native compiler,
it's in <tt>gcc:lib/gcc/ppc-amigaos/<i>compiler-version</i>/specs</tt>. Most likely, your compiler will already have this added to it's specs file.</p>
<p>Profiling makes use of a special PowerPC facility called the Performance Monitor. It
allows to "mark" tasks and count only during while a marked task is running. This allows
performance analysis to be made independant of the actual system load. The Performace Monitor
is available on all PowerPC models supported by AmigaOS 4 except for the <tt>603e</tt>, and
embedded versions of the PowerPC like the <tt>405</tt> and <tt>440</tt> series. Consult the manual
of the appropriate chip for more information.</p>
<h2>6. Conventions and design issues</h2> <h2>6. Conventions and design issues</h2>