On Optimization

A few days ago, I became curious about a problem. It wasn't necessarily my problem, but it had been something I'd encountered throughout the past few years I guess. This time around, it was dealing with file path manipulation, so I decided to think of every way I'd seen file path manipulation done and check the speed, GC, and RAM usage throughout each test and see which method was fastest and less RAM dependent. I am not claiming these tests are thorough or even accurate, but the results are interesting. One thing I noticed was that it didn't matter what test was ran first, it always had a large gap in the RAM and GC usage, so I assume it has to do with loading dependent libraries and them being cached in later methods. This recreated every file path on my windows partition (/windows) since I knew I wouldn't get any permission errors.

The main lines in the code that I was testing are the following:

...
string fileName = d + dirSeparator + info.Name; //dirSeparator is defined once at the beginning of the method.
...
string fileName = d + "/" + info.Name; 
...
string fileName = d + Path.DirectorySeparatorChar + info.Name;
...
string fileName = Path.Combine(d, info.Name);
...

And the results:

bperry@bperry-desktop:~/Projects/PathingSpeedTest/PathingSpeedTest/bin/Release$ mono PathingSpeedTest.exe 
Building cache...

Starting escape from outside iterations...
Took 23 seconds
Most RAM: 78932kb (Started with 78800kb)
Most GC: 620kb (Started with 604kb)

Starting escape from inside iterations...
Took 29 seconds
Most RAM: 78828kb (Started with 78828kb)
Most GC: 616kb (Started with 612kb)

Starting environment escape...
Took 29 seconds
Most RAM: 78828kb (Started with 78828kb)
Most GC: 632kb (Started with 600kb)

Starting Path.Combine() test...
Took 29 seconds
Most RAM: 78828kb (Started with 78828kb)
Most GC: 616kb (Started with 612kb)

bperry@bperry-desktop:~/Projects/PathingSpeedTest/PathingSpeedTest/bin/Release$ 

May not be the best way to test this, so I am open to suggestions. Source code is here (is monodevelop, so not sure if it will open in VS).