Re: Xen & VMI?

From: Zachary Amsden
Date: Wed Mar 07 2007 - 04:17:52 EST


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
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