Measure efficiency of multicore processor - or do you really need so many cores?

This is CPU benchmark which demonstrates processor characteristics and performs some heavy calculation using threads to present correlation to one or more processor cores.
Map reduce is used to calculate occurrences of 16K integers with range [1, 1000].

Code is available on Github: github.com/miktam/MultiCoreAndroid
Tags: processor, CPU, benchmark, speed, test, multithreaded, thread.

Recent changes:
Version 4.3:
Added settings for number of threads used in benchmark.
Bug fixes.

Version 4.2:
Changed layout, bug fixes.

Version 4.0:
Expanded menu with statistics and information about benchmark.

Version 3.0:
Introduced menu.

Version 2.0:
Introduced Map Reduce instead of Pi calculation.

Version 1.0:
Initial release