There is no tool to measure complexity; you need to calculate it using formal analysis.
Time spent can be measured with tic and toc. Be warned, though, that they measure elapsed time, not CPU time. You would need to use your operating system facilities to measure cpu time. For higher precision time measurement, consider using the FEX contribution "timeit". The technical differences between "elapsed time" and CPU time can be considerable.
You cannot calculate "speed" or "performance" without some detailed operating system and hardware tools that are specific to the hardware you are using.
On modern CPUs, measuring performance of a section of code can be quite difficult and requires making a whole series of decisions about what "performance" means.
