Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!ucsd!helios.ee.lbl.gov!surf.ee.lbl.gov!leres
From: leres@surf.ee.lbl.gov (Craig Leres)
Newsgroups: comp.unix.wizards
Subject: Re: Real-Time Granularity: A Query
Message-ID: <4552@helios.ee.lbl.gov>
Date: 4 Jan 90 04:28:51 GMT
References: <598@codonics.COM>
Sender: usenet@helios.ee.lbl.gov
Reply-To: leres@helios.ee.lbl.gov (Craig Leres)
Organization: Lawrence Berkeley Laboratory, Berkeley
Lines: 16
X-Local-Date: 3 Jan 90 20:28:51 PST

By the way, the Sparcstation's clock has a microsecond register; we
were able to modify the nit code to take advantage of this when
constructing the nit timestamp.

While this is a vast improvement over the 20ms clock other Suns provide
(10ms if you've hacked the kernel like me) it's still not perfect for
network analysis. When packets arrive close together, you tend to be
measuring the time it takes nit to process a packet instead of the
inter-packet spacing. What we need is an ethernet interface that
installs per-packet timestamps in hardware!

Don't have any sun4c source so I haven't hacked gettimeofday() to use
it yet. But I gave the nit enhancements to a buddy at Sun and he it was
a good idea and would see about sticking it in SunOS.

		Craig