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From: allyn@sdcsvax.UUCP
Newsgroups: comp.unix.wizards
Subject: Re: AT *speed* (was Re: 4.3 bsd for PC/AT)
Message-ID: <3891@sdcsvax.UCSD.EDU>
Date: Wed, 16-Sep-87 21:43:10 EDT
Article-I.D.: sdcsvax.3891
Posted: Wed Sep 16 21:43:10 1987
Date-Received: Sat, 19-Sep-87 05:54:56 EDT
References: <9338@brl-adm.ARPA>
Organization: U.C. San Diego
Lines: 80

In article <9338@brl-adm.ARPA>, donn@rice.EDU (Donn Baumgartner) writes:
> In response to my claim that the AT (roughly) benches above the vax,
> Larry McVoy basically complained that he had seen just the opposite,
> albeit "only a little tiny bit slower", and proceeded to give standard numbers
> associated with AT machine's disk speeds, cpu speeds, and memory count.
> The jist being that an AT running some non-BSD un*x system appeared to be
> slower than a vax 750 (probably not running xenix).

i've just been doing some (trivial) benchmarks of an IBM PC/AT (and the other
PC models), a VAX-11/780 and a SUN-3/110.  they might be of slight interest 
to somebody, so here they are.

please no flames about this benchmark.  it obviously doesn't test any i/o,
context switching, system calls or anything else.  just some probably useless
measurement of processor speed.  all timing was done with either the csh 
built-in "time" or /bin/time.  all machines were in multi-user mode, so the 
time reported is just the sum of the user and system time, not the elapsed 
time.

operating systems:
VAX	4.3 BSD		(looks to have an FPA from the benchmarks)
SUN	SunOS 3.2
PC/AT	PC/IX 1.1	(has an 80287, ~8.5 MHz processor speed)
PC/XT	PC/IX 1.1	(has an 8087)
PC	PC/IX 1.1	(uses PC/IX software floating point simulation)

this (admittedly stupid) benchmark (10,001,000 additions/increments):

main()
{
	register x, y;

	for (y = 0; y < 1000; y++)
		for (x = 0; x < 10000; x++);
}

took the following times (seconds user+system, not wall clock):
sun-3/110 (chems1.ucsd.edu)	8.5
vax-11/780 (sdcsvax.ucsd.edu)	22.2
ibm pc/at (robin.emu.ucsd.edu)	26.3
ibm pc/xt (sdemu.ucsd.edu)	101.1

the same program with the declaration line changed to:

	int x, y;

(without registers) took:
sun-3/110		15.8
vax-11/780		33.2
ibm pc/at		45.3
ibm pc/xt		205.9

this floating point program (1,000,100 floating point add/increments):

main()
{
	float x, y;

	for (y = 0; y < 100; y++)
		for (x = 0; x < 10000; x++);
}

took:
vax-11/780			20.5
sun-3/110			52.5
ibm pc/at			88.6
ibm pc/xt (sdemu.ucsd.edu)	135.0	(8087)
ibm pc (kiwi.emu.ucsd.edu)	5701.7	(software fp) (that is NOT a typo)
					(that's over 1.5 HOURS)

and the same program with variables changed to double from float:
vax-11/780			17.2
sun-3/110			65.7
ibm pc/at			95.2
ibm pc/xt 			146.2	(8087)
ibm pc 				?	(software fp) (i wasn't about to wait)
-- 
 From the virtual mind of Allyn Fratkin            allyn@sdcsvax.ucsd.edu    or
                          EMU Project              {ucbvax, decvax, ihnp4}
                          U.C. San Diego                         !sdcsvax!allyn