Multi-processor kernel causes time to go faster?

Daniel McNamara daniel at cit-linux.net
Wed Jan 23 19:16:44 EST 2002


Hey guys,

Well my foray into the wonderful world of dual processors continues. I now
have Linux installed and I have built two kernels, both exactly the same
except for the fact once has mutli-processor support and the other does not.

What I've found out is that whilst running the mult-processor kernel the
system clock speeds up considerably. By using NTP and a stop watch I was
able to determine that the system clock runs at exactly twice it's speed (eg
One minute "real" time = 2 minutes system time). Switch over to the single
processor kernel and the system clock runs as normal. I've done a bit of
searching on the web and found some information but a lot goes over my head.

My question is why does it run twice as fast and is there anyway of
adjusting for / stopping it (without having to do a NTP sync every minute).
For the sake of sanity and correctly stamped log files I've crippled the
machine to the single CPU kernel. That's the same effect as installing
Windows on it. Can anyone help me out how I can utilise the power of both
CPU's without going through the insanity of accelerated system time?

Cheers

Daniel





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