Jan Kiszka wrote:
Jan Kiszka wrote:
...
What about other time sources on x86? Which systems already have HPET
these days, and does this source not suffer from frequency scaling? I
once read that HPET is quite easy to program, is this true? IOW, would
it be worth considering to add this to the HAL?
There are actually only few registers:
http://www.intel.com/hardwaredesign/hpetspec_1.pdf
Even a replacement for the TSC is available ("Main Counter"), but I
guess that some effort will be required to replace all direct usages of
rdtsc in the current Xenomai code, right?
There should not be any direct usage, at least into the generic code, since it is
aimed at running over the event-driven simulator too. Actually, the same goes for
the x86-specific code, since we do support using the 8254 as an alternative to the
TSC.
Jan
--
Philippe.
