Re: Xen & VMI?

Zachary Amsden
2007-03-07T09:17:13Z

Ingo Molnar wrote:
> For example, VMI_CALL_SetAlarm takes a 'cycles' argument. Cycles is a
> quite bad unit for an API, it should be absolute time, nanosec or
> picosec based instead. We could easily see CPUs that have /no concept of
>

Actually, putting the unit in terms of cycles is more portable and
flexible. Rather than perform a conversion from cycles to
nano/femto/pico seconds, the raw cycle count is exposed, along with the
current clock frequency. This allows the timer infrastructure to merely
do one conversion, from cycles to real time, rather than converting to
an arbitrary time unit which may change with operating systems and time
and thus break the ABI.

Zach