[Beowulf] ...Re: Benchmark results

Josip Loncaric josip at lanl.gov
Thu Jan 8 18:33:28 EST 2004


Andrew Piskorski wrote:

> Would DJB's clockspeed, taiclock, etc. stuff be any better than ntp
> for that?  

Interestingly enough, DJB says that after he applied clockspeed 
compensation, his machine drifted only 0.21 seconds in three months. 
This would imply long term clock stability of about 0.027 ppm, but as 
Jim already pointed out, short term stability usually isn't as good. 
Using the random walk assumption, DJB's clock could drift 75 
microseconds in either direction each second (at random), and still meet 
these long term stability results...  While full NTP may be too much, 
some NTP-like approach is probably needed...

Sincerely,
Josip

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