Arnd Bergmann <arnd@xxxxxxxx> writes: > > To clarify: current_kernel_time() uses at most millisecond resolution rather > than microsecond, as tkr_mono.xtime_nsec only gets updated during the > timer tick. Ah you're right. I remember now: the motivation was to make sure there is basically no overhead. In some setups the full gtod can be rather slow, particularly if it falls back to some crappy timer. I think it would be ok if it falls back to jiffies if TSC or a similar fast timer doesn't work. But the function you're using likely doesn't do that? > Has that time scale changed over the past 16 years as CPUs got faster > (and system call entry times slower down again with recent changes)? Maybe a bit, but not substantially. -Andi
