How to optimize a C application?

Question

C++ / C#

When implementing complex image filtering algorithms, I ran into the problem of optimizing applications in terms of running time and the amount of memory used. If someone knows some good books on C-code optimization please tell me.

Answer 1

Use a profiler to find problem areas. I work with https://developer.nvidia.com/nsight-systems, but there are others, including more popular options.
First of all, it is worth optimizing the asymptotic complexity.
Further it is possible to think of parallelization on some flows.
If everything is already optimal, you can look at micro optimizations:
https://habr.com/en/company/intel/blog/257309/
Well, in addition, you can use CUDA for GPU processing

Answer 2

start with the grandfather of the whip, or something