I want to make a wrapped acces type for certain internals of one of classes and I have some performance questions

Question

I am writing an abstract matrix class (and some concrete subclasses) for use on very differing hardwares/architectures, etc. and I want to write a row and column type that provides a transparent reference to the rows and columns of the matrix.

However, I want to tune for performance, so I'd like this class to be essentially a compiler construct. In other words, I'm willing to sacrifice some dev time to making the overhead of these classes as small as possible.

I assume all (small) methods would want to be inline? Keep the structure small? Any other suggestions?

Answer 1

Don't do it. Write your code naturally. Make an elegant design and clear design. Make it work. Then, run it with a profiler and see if you have any performance holes.

Answer 2

Design for efficiency golden rule number 1 is to really properly fully completely totally understand and appreciate all of the nuances of the environment in which you are working.

Including, but not limited to:

• Understanding the costs of each compiler construct you are using
• Understand how the compiler uses memory
• Do a proper design on the back of an envelope or napkin. If it doesn't fit you're in trouble.
• Build small examples and test / disassemble
• Revisit the design.

Then write some realistic test cases and test on the disparate hardware to identify if there are performance issues; I've done this a few times and unless you're writing in assembler the performance hit can be in the strangest places.

If it's too slow add hardware. If you can't add hardware optimise.