Profiler Speed

[Tom S]

dsimcha wrote:
> I'm working on optimizing some code now, and a nagging issue that I've been
> meaning to bring up is how slow stuff runs when profiling is turned on.  It
> seems that, given any code that's slow enough to be worth
> profiling/optimizing, the DMD profiler slows it down further, to the point
> where it's impractical to profile because it would take forever to get the
> results.  Does anyone have any tips for speeding this up?

You could try using an external non-intrusive profiler. If you compile 
your stuff with GCC on *nix, I've been hearing that kcachegrind is 
pretty awesome: http://kcachegrind.sourceforge.net/html/Home.html
If you'd like to profile a DMD-Win-compiled executable, I've written a 
simple tool to do it which is similar to the Sleepy profiler: 
http://sleepy.sourceforge.net/ ( Sleepy doesn't work with DMD-made 
executables ): http://team0xf.com:1024/dprof/ ; if you compile Main.d 
and run it, passing the name of your executable as a parameter, it will 
attach to it (your app must be compiled with -g and without -O). Then it 
pauses the target thread a few thousand times a second, checking its 
register states and finding the currently executed function. The stats 
are gathered and when you hit Enter, you're provided with some info. The 
program is a pretty simple one and may not do what you'd like, however 
the actual profiler is a separate lib (dprof.Profiler) which could be 
used in a more sophisticated way. So far, I've used it to successfully 
optimize some ray-tracing code and remove a few bottlenecks from Hybrid.

-- 
Tomasz Stachowiak
http://h3.team0xf.com/
h3/h3r3tic on #D freenode