Subject: Re: NTP clock drift worsened around June 20?
To: Jonathan Stone <jonathan@DSG.Stanford.EDU>
From: Erik E. Fair <>
List: tech-kern
Date: 08/06/1997 00:25:20
Perhaps the scheduler? I wonder how much of the variation in NTP is the
vagaries of the existing scheduler; a re-examination of its assumptions in
the light of both modern systems architecture, and the various uses that
the system gets put to would be a very good thing to do. We should also
give a thought to adding some facility for making real-time scheduling
latency guarantees for things like the NTP daemon, CD-R writers, X window
system managers, and so on.

The overarching issue is that we should probably start doing some
benchmarks to see if we can identify where the kernel time is going (and
see about other overheads), and preferably tune things a bit before the 1.3
release (whenever that is going to be). I just finished reading the paper
that Kevin Lai and Mary Baker did (and that you consulted on) on
FreeBSD/Linux/Solaris performance on a 100MHz Pentium; offhand, I'd say
collecting that data for NetBSD 1.2 on each platform it supported as a
baseline would be a place to start. Then we go get it for each platform on
-current, and see what improved, and what got worse...

	Erik <>