Working on converting apps from x86 to x64 to be able to measure performance differences and a few other things but I ran into a strange issue yesterday morning which I've been trying to find an answer for today.
The main question, which I probably won't get answered here, is why the performance is +30% for x64 in debug mode but -10/20% in release? It's fairly strange and I want to find an explanation of that and that's why I've been trying to use VTune for the last 3-4 hours or more. It takes some time to get a little bit of knowledge how to actually run it and get some info that I want, and when I finally got it I don't know really what to read out from it...
I'm running VTune integrated in VS2005, the application is single threaded and performance is tested through ACT which records and playbacks a certain sample.
To the question here:
What to look for when I'm comparing 32 & 64-bit builds, should I concentrate on Instructions Retired, Clockticks or CPI? I don't care too much about optimizing the code later on, the main issue is where the performance difference is 32-64 bits.
Can I check release builds the same way as Debug and get data from the functions, not only assembler code? How?