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From: grandi@noao.UUCP
Newsgroups: net.lang.f77
Subject: Re: xf77 compiler ?
Message-ID: <357@noao.UUCP>
Date: Fri, 22-Jun-84 11:50:32 EDT
Article-I.D.: noao.357
Posted: Fri Jun 22 11:50:32 1984
Date-Received: Sat, 23-Jun-84 03:47:45 EDT
References: <32400001@uiucuxc.UUCP>
Organization: Natl. Optical Astronomy Obs.  Tucson AZ USA
Lines: 39

*
	My understanding of the LINPACK Benchmark is that xf77
represents the BSD 4.2 f77 compiler (with optimization on).
However, as regular readers of this newsgroup know, the 4.2 f77
optimizer is FULL of bugs.  Thank the Gods of Fortran for Donn Seeley
and his bugfixes that at least seem to make the compiler reliable with
the optimizer off.  SO, if all the bugs can be rooted out, the 4.2 f77 
compiler is at least close to the VMS compiler in execution speed.  But
it is sure slow when compiling!  HOWEVER, DEC has just announced that the f77
compiler that will come with version 4.0 of VMS will increase execution
performance by 10 - 50%.

	For those of you interested in the actual benchmarks, they are
taken from "Performance of Various Computers Using Standard Linear
Equation Software in a Fortran Environment," Jack J. Dougarra,
Mathematics and Computer Science Division, Argonne National
Laboratory, 10 Jan. 1984.  Unfortunately, I have misplaced my copy of
this report and can only quote from a bowderlized version reprinted in
the Astronomical Image Processing Circular (#10).  Linpack routines SGEFA 
and SGESL were used for problems of order 100.

Computer/Compiler               Double-Precision Mflops  Single-Precision Mflops
--------------------------------------------------------------------------------
Cray X-MP/CFT                     21.0
CDC Cyber 205/FTN                  8.4
Amdahl 5860/H enhan (opt=3)        3.9                    5.5
IBM 3081K/H enhan (opt=3)          2.1                    2.4
DG MV-10000/f77 (opt=3)            0.30                   0.39
VAX 11/780 + FPA/VMS-f77           0.13                   0.21
VAX 11/780 + FPA/UNIX(4.2)-f77 opt 0.11                   0.20
Ridge 32/f77                       0.12                   0.20
VAX 11/750 + FPA/VMS-f77           0.10                   0.14
IBM 4331/H (opt=3)                 0.038                  0.088
VAX 11/730 + FPA/VMS-f77           0.036                  0.047
IBM PC-XT/370/H (opt=3)            0.031                  0.040
Sun 2 + FPA/UNIX(4.2)-f77 opt      0.022                  0.039
-- 
Steve Grandi, National Optical Astronomy Observatories, Tucson, AZ, 602-325-9228
      {allegra,arizona,astrovax,decvax,hao,ihnp4,lbl-csam}  !noao!grandi