High-resolution clock for metering on Sun 3's available?

[Dan Weinreb]

I would like to do some metering and performance analysis for which it is
essential to have a real-time clock of higher resolution than the roughly
16ms clock provided on my Sun 3. 

Ideally, I'd like a clock with microsecond resolution.  It should ideally
come with a device driver that lets me map the clock directly into my
virtual address space, so that I can read the clock without incurring the
overhead of a system call.  Super-ideally it should be attachable to a Sun
3/60, but if it could plug into a Sun 3/160, that would be fine.

Does anyone know where I might be able to buy such a device?  Thanks.

Daniel Weinreb		Object Design, Inc.
dlw at odi.com   (or ...!uunet!odi!dlw)