I know that dispatch_time
is the time according to device clock and if the device goes to sleep the clock sleeps too. On the other hand the dipatch_walltime
is time according to wall clock, which never goes to sleep. My questions is, is there any difference, performance-wise or other, to use one or the other in different situations? Can somebody give me some more details, because the Apple docs are not exhaustive.
For example I'm writing a Timer
class which operates on certain intervals. Also the leeway could be 10 to 30 secs. Which one should I use dispatch_time
or dispatch_walltime
, performance-wise.