Path: utzoo!attcan!uunet!husc6!ogccse!cvedc!nosun!sns4.fpssun.fps.com!lfm
From: lfm@fpssun.fps.com (Larry Meadows )
Newsgroups: comp.sys.intel
Subject: Re: Dhrystones/Whetstones for i860
Message-ID: <494@sns4.fpssun.fps.com>
Date: 24 May 89 16:56:05 GMT
References: <212@riunite.ACA.MCC.COM>
Reply-To: lfm@sns4.UUCP (Larry Meadows )
Organization: FPS Computing, Beaverton,OR
Lines: 51

In article <212@riunite.ACA.MCC.COM> rfg@riunite.UUCP (Ron Guilmette) writes:
>Does anybody out there have any Dhrystone or Whetstone numbers for
>the i860?  If not, why not?

From intel published material:
Dhrystones:
	Measured 69,000 Dhrystones (V1.1) @ 33.3 MHz 
	  Green Hills C V1.8.5
	  Estimated 90K (V1.1) and 85K(V2.1) @ 40MHz w/ improved compiler
Whetstones:
	Measured 20Kwhets (double) and 25.6 Kwhets (double) @ 33.3 Mhz
	  Green Hills Fortran 1.8.5
	  Estimated 25 and 32 Kwhets @ 40MHz w/ improved compiler
Linpack 100x100 (Double precision):
	6.1 Mflops (compiled), 11 (coded BLAS) @33.3MHZ
	  Green Hills Fortran 1.8.5 and VAST 2.25N1 (vectorizer)
	  Estimated 10 and 13.2 Mflops @40MHz w/ improved compiler

Several compiler optimization switches were used when compiling these
benchmarks.  Note that these numbers have been available for some time.

>I see where Intel has gotten a lot of publicity from their claim of
>80 Mflops "peak" (single precision) and 60 Mflop "peak" (double
>precision).  Well, I've finally had a chance to look over the
>instruction set, and it is bloody obvious that it is going to take
>the compiler writers a LONG LONG TIME before they can get normal
>applications to compile down to code that will even approach 2/3
>of these "peak" figures.

You are correct in saying that this is a difficult compiler problem; however,
there are several companies that have been writing compilers for these
kinds of machines for a long time.

>One last question.  Considering all of the i860's (complicated)
>parallelism would *could* be productively used, I'd like to know
>in Intel (or anybody else) is building (or has built, or is planning
>to build) some software tool which can gobble up mediocre code and
>re-mangle it into execelent code.

Good compilers that include vectorizing and parallelizing transformations
and software pipelining can do this for source code.
If are talking about doing this for assembly code it is probably not worth
the effort -- much more improvement is possible by incorporating these
sorts of transformations into the compiler since more information is available.

Actually I think that the i860 is quite an achievement; it will perform
especially well on vectorizable scientific fortran.  The linpack number
is excellent, especially for a chip that costs $750.
-- 
Larry Meadows @ FPS			...!tektronix!fpssun!lfm
					...!nosun!fpssun!lfm