[ntp:questions] Dual-core systems - AMD - Windows Vista

Danny Mayer mayer at ntp.isc.org
Mon Dec 3 13:32:28 UTC 2007


Martin Burnicki wrote:
> Danny Mayer wrote:
>> David J Taylor wrote:
>>> Thanks for your reply.  Perhaps my recollection is at fault here, but I
>>> recall that NTP on Windows uses some interpolation technique to overcome
>>> timer granularity, and that the interpolation used a CPU counter.
>> We are intending to implement that but we haven't done so yet.
> 
> Huh? Danny you should know the code is already there for many years ...

No, I was talking about Peter and Terje's additional interpolation code.

>> There is one other thing that needs to be considered. This is a 64-bit
>> system> In that case it's possible that the code may need to be changed
>> to deal with it properly. For example using the VS 2005 compiler I have
>> found that it uses a 64-bit integer instead of 32-bit integer for
>> time_t. This could affect the quality of the results, it's hard to say.
> 
> Shouldn't this only matter when the 32 bit time_t overflows?

It's hard to know. I first ran into the issue when I compiled BIND with
VS 2005 and it fell over almost immediately and it wasn't an overflow
issue. However on a 32-bit O/S on 64-bit hardware the results are really
uncertain.

Danny





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