fedorkow@BBN-VAX.ARPA (Guy Fedorkow) (10/01/85)
In the process of evaluating computing environments for running
Magic and other Berkeley VLSI tools at BBN, I have compared the
performance of our VAX 11/785 and Sun Microsystems workstations. This
memo describes the method used and the results obtained, and as such, it
may be of interest to others contemplating the purchase of hardware
to support VLSI work. Questions or comments may be directed to
fedorkow@bbn-vax
A visit to Sun Microsystems in Lexington MA
Guy Fedorkow, BBN, Sept 23, 1985
After several attempts, I finally had a chance today to use a sun-3/160
workstation to run a Magic benchmark. It was worth the wait; the new
Sun-3 systems seem to be real performers.
The system that I used was a Sun 3/160C, a color workstation with
140 Mb of local disk, 4Mb of main memory, and a 68020/68881 CPU.
The machine had the sun graphics processor, but it apparently has
very little impact on the current version of Magic.
The tests that I ran involved a series of manipulations of the
BBN Butterfly switch chip, excluding pads, etc. This is an nmos chip,
using just under 2,000 transistors. The basic intent of the test was to
isolate the performance contributions from graphics display vs
compute activity, for small and large chips. The 2,000 transistor
switch chip was flattened to simulate the effects of a large chip.
Results in this test sequence are compared to a VAX 11/785.
Tests were run on the VAX early in the morning, at a time when
serious users were still asleep. No other precautions were taken
to ensure uniform vax loading.
Partial results are also presented for the same test run on a
sun 2/160, the machine without the new 68020 board. This set of tests
could not be completed due to changes in a new version of magic.
Timing measurements are expressed as minutes:seconds. Don't try
interpret values to five decimal places -- all measurements were done
with an ordinary stop watch.
The Tests
Command Vax Sun 3/160 Sun 2/160
/* cause the entire chip to be displayed */
:expand all 3:54 1:13 3:40
/* check the entire chip - a test of compute speed */
:drc check 0:42 0:31 1:28
/* flatten the hierarchy */
:yank 0:30 0:28 3:45
:load new
/* stuff into a new cell */
:stuff 0:40 1:25 it broke
/* note the effects of paging are beginning to show */
/* write a 330 Kbyte file */
:cif write 1:00 2:15
:extract all 0:36 3:00
Summary
The sun 68020 implementation seems to be fast indeed. Pictures
are drawn about 3 times faster than the VAX with an AED-512. Computing
seems to on a par with the 785, as long as the core image is small
enough to fit into ram. Disk I/O is still slow -- once paging sets
in, the sun slows down a lot. The same result has been observed in
previous tests with a 2 Mbyte sun without the 68020 upgrade. In that
case, performance with magic fell by a factor of ten once serious
paging started to happen.