Stopwatches

Simple stopwatch objects with the following member functions:

• void start() start timing
• double stop() stop timing (return total time)
• double stop_d() stop timing (return time since last start)
• double reset() set elapsed time to 0.0 (return total)
• double read() read elapsed time (total)

The following stopwatches are available:

• stopwatch measures CPU time (userpace + system)
• stopwatch_u measures CPU time in userspace incl. children
• stopwatch_us measures CPU time userspace + system incl. children
• stopwatch_e measures elapsed (wall clock) time