IIRC, the usual recommendation is to compile your own
kernel with system
timer set to 1000 Hz.
I know. Compiling a custom kernel on Ubuntu (in a package-manager
controlled way) is not fun.
It's amazing, though, that the system has an RTC clock and a HPET timer,
with microsecond precision, yet I need to rely on the Hz variable to
obtain accurate timing. Truly amazing -- the whole snd-rtctimer vs
RTC_CLASS story, the broken hpet module in ALSA, the unfinished hrtimer...
-- Dan