Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!sdd.hp.com!hplabs!hpfcso!maf
From: maf@hpfcso.FC.HP.COM (Mark Forsyth)
Newsgroups: comp.arch
Subject: Re: More Snake bytes.
Message-ID: <8840021@hpfcso.FC.HP.COM>
Date: 1 Apr 91 18:41:54 GMT
References: <2004@kuling.UUCP>
Organization: Hewlett-Packard, Fort Collins, CO, USA
Lines: 56

>From: mash@mips.com (John Mashey)
>
>PLEASE: do we have to keep seeing cost/MIPS, where everybody
>computes mips differently.  I'll express a little irritation at this:
>people MIGHT have computed Price/SPECmark and Price/SPECint,
>where the latter is an intelligent approximation to Price/VAX-mips-integer.

And why not Price/SPECfp also ?  Don't workstation customers still care
highly about performance on FP applications ?  Why did SPEC choose six
FP intensive benchmarks if these are not important ?  Is the importance
of a benchmark suite proportional to how competitive MIPs is on it ?
Why not also include I/O, graphics, X11, etc. ?

>Of course, if I had a machine whose SPECfp is substantially higher than
>its SPECint, and I were a marketeer:
>	a) I'd quote SPECmarks to get the effect from the FP
>	b) I'd quote mips-ratings (based on dhrystone) to get a good-looking
>	price/mips.
>	c) I'd avoid quoting a price/SPEcint, although that is a hugely
>	more predictive number, and whose data HAD to be available to
>	compute the overall SPECmark....  even if the value is quite good,
>	(which it is) because b) is likely to be better....

And if I were HP I'd quote (which they have) performance on many other
types of workloads in a 42 page performance brief. It includes all of
the SPEC components as well as Workstation Labs' Khornerstones, X windows
(x11perf 1.2), networking, disk I/O, Ansys (scientific applications), 
graphics, as well as the "toy" benchmarks (which are included because 
customers and press ask for them, and think you are hiding something if
you try to tell them it's not important).

The $/anything comparisons you are so miffed about come from the press
(UNIX Today, I believe), not HP documentation. 

>
>Summary: Snakes look like a good implementation of a good architecture;
>the FP got a good boost, mostly from the new compilers avail in June;

Even without the new compilers the FPspec/MHz (0.94) is about 30% higher
than the DECstation 5000/200 (0.74) and absolute FP spec is about 2.6 
times.  The new compilers raise these to 43% and 4.9 times, respectively. 

>the integer performance remains closely on
             ^^^^^^^^^^^ 
>the line of well-implemented single-issue, 1-level cache RISCs,
>i.e., SPECint = .75-.80X MHz.

The integer "performance" is 2.7 times the 25 MHz R3000 (DEC 5000/200). 
Speed is an extremely important high performance design technique. If 
you normalize it out you end up with a truely meaningless indicator of
performance and one that users shouldn't and don't care about.

>
>-john mashey	DISCLAIMER: <generic disclaimer, I speak for me only, etc>

- Mark Forsyth