How to Optimize Loops

• Sometimes you'll encounter loops, or recursive functions, that take a long time to execute and are bottlenecks in your system

• First, search for a way of removing the loop entirely before looking to optimise

• Recursion, can lead to code being more complex and harder to understand, if you value development performance over system performance then consider replacing these

  • use of functinoal ways, ie streams, lambdas might be better

• Optimising loops

  • Move as much stuff out of the loop, so actions are not repeated

    • Example

      • Remove floating point operations.

      • Don't allocate new memory blocks unnecessarily.

      • Fold constants together.

      • Move I/O into a buffer.

      • Try not to divide.

      • Try not to do expensive typecasts.

      • Move a pointer rather than recomputing indices.

      • String creation

  • If you are looping of data in memory, but this came from a database, instead of doing it in code, let the database do it for you (it is optimised to handle this)

  • These can be language specific