Small interesting ISC vs. SCO benchmark

Tim Bray tbray at
Sat Sep 30 03:01:40 AEST 1989

When we were casting about trying to decide whether to go ISC or SCO, one
consideration was performance.  Anyhow, now we're shipping software for
both (getting tired of switching disk cables, too) and perhaps a little
benchmark info would be interesting.

This is an AMI 20 Mhz motherboard, 4Mb memory, vga, 150 Mb Maxtor, nothing
fancy.  Don't have the OS release numbers handy, but they're both basically
the latest: guess that means ISC 2.0.3 and SCO 2.3.3?

The application is 8,000 (very very compact uncommented) lines of C
that build and minimize N-tape deterministic finite automata defined in
a regular language grammar. (Yes, this is a commercial piece of
software; a 2-tape automaton can be used to drive a general text
transduction process in somewhat the same fashion as yacc, but this
thing can eat grammars for breakfast that make yacc roll over and die.)
Compiled -O on both systems.  Note that it uses sbrk() not malloc().

In this instance, the program builds and minimizes a 2-tape automaton that
ends up with 1,193 states and 40,715 transitions.  It reads in a grammar
that is 3,225 bytes in size and stores the automaton in a file that is
326,215 bytes in size.  It uses up to 2.5 Mb of virtual memory during
its run; both SCO and ISC paged quite heavily, judging by the flashing of 
the disk light.


System	User time	System time
ISC	181		2.3
SCO	174		4.2

Elapsed time was 7 min. on Unix, didn't measure it on Xenix, but it felt 
about the same.

Sooo... for one example of a compute-intensive application, we observe no
significant difference in the performance of compiled C code.

Just another data point on the great curve in the sky...

Cheers, Tim Bray, New OED Project, U of Waterloo

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