Re: Need better is_better_time_interpolator() algorithm

[George Anzinger <george@mvista.com>]

Alex Williamson wrote:
> On Fri, 2005-08-26 at 08:39 -0700, Christoph Lameter wrote:
> 
> 
>>I think a priority is something useful for the interpolators. Some of 
>>the decisions about which time sources to use also have criteria different 
>>from drift/latency/jitter/cpu. F.e. timers may not survive various 
>>power-saving configurations. Thus I would think that we need a priority 
>>plus some flags.
>>
>>Some of the criteria for choosing a time source may be:
> 
> 
> Hi Christoph,
> 
>    I sent another followup to this thread with a patch containing a
> fairly crude algorithm that I think better explains my starting point.
> I'm sure the weighting and scaling factors need work, but I think many
> of the criteria you describe will favor the right clock.
> 
> 
>>1. If a system boots up with a single cpu then there is no question that 
>>the ITC/TSC should be used because of the fast access.

We need to factor in frequency shifting here, especially if it happens 
with out notice.


~
-- 
George Anzinger   george@mvista.com
HRT (High-res-timers):  http://sourceforge.net/projects/high-res-timers/