Re: [Valgrind-users] Pre-instrumented vs JIT instrumentation

SourceForge Headquarters 225 Broadway Suite 1600 San Diego, CA 92101 +1 (858) 422-6466

<!doctype html public "-//w3c//dtd html 4.0 transitional//en">
<html>
Valgrind, unlike Rational suite tools, does not "instrument" anything.&nbsp;
That's the beauty of it - you don't need to recompile (or in case ot Quantify
re-link) the application.&nbsp; The difference is that Rational tools embed
extra code inside your object files and libraries - for memory or performance
profiling. As a result, executable size, shared libraries sizes are huge
and executiion suffers greatly (esp. with purify). Valgrind, on the other
hand, runs your application on a synthetic CPU, all the machine instructions
of your app are executed by Valgrind on this CPU and memory/performance
profiling is done there, not in your app code.&nbsp; As far as Quantify
comparison, cachegrind sking gives you much more information - e.g. Quantify
does not report cache usage profile.
<p>Last but not least - Valgrind is free, has MUCH&nbsp;better developer
support, and is updated more frequently.
<br>Downside - only runs on x86 Linux, exactly because of synthetic CPU
- porting it to other platforms is too much work, so developers chose the
most popular platform.
<p>Regards,
<br>Alex
<p>Mike Bresnahan wrote:
<blockquote TYPE=CITE>I am new to valgrind, but I have used Rational Quantify.&nbsp;
Excuse if this is
<br>a FAQ, but I could not find anything in the FAQ nor in the mailing
list
<br>archive.
<p>I am curious why valgrind chooses to instrument on-the-fly every time
the
<br>application is executed rather than instrumenting the application ahead
of
<br>time and reexecuting the same instrumented executable each time, a
la
<br>Quantify.&nbsp; To my perhaps naive mind it seems like instrumenting
on-the-fly
<br>is less efficient.&nbsp; Can someone lend some insight?
<p>Mike
<p>-------------------------------------------------------
<br>This SF.net email is sponsored by:&nbsp; Etnus, makers of TotalView,
The best
<br>thread debugger on the planet. Designed with thread debugging features
<br>you've never dreamed of, try TotalView 6 free at www.etnus.com.
<br>_______________________________________________
<br>Valgrind-users mailing list
<br>Val...@li...
<br><a href="https://lists.sourceforge.net/lists/listinfo/valgrind-users">https://lists.sourceforge.net/lists/listinfo/valgrind-users</a></blockquote>

<pre>--&nbsp;
Alex G. Ivershen&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Inet Technologies, Inc.
Network Products Dept.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 1500 N. Greenville Ave.
Inet Technologies Inc.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Richardson, TX 75081
Phone: +1-469-330-4295&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; USA

"Computer games don't affect kids; I mean if Pac-Man affected us as kids, we'd&nbsp;
all be running around in darkened rooms, munching magic pills and listening to
repetitive electronic music." -- Kristian Wilson, Nintendo, Inc</pre>
&nbsp;</html>