Floating-point benchmark comparison

[mohan ramamurthy]

Given below are the results of a study comparing the performance of
various computers (workstations as well as supercomputers) for six
floating-point-intensive Fortran codes.  These programs represent what you
might call a hierarchy of "typical" geophysical fluid dynamics models.
Identical codes were used on all machines, and no effort whatsoever was
made to explicitly optimize the codes on a particular machine - other than
the use of the highest available compiler optimization.  Some codes have a
large percentage of scalar computations (e.g., the QG model spends over 95
percent of its time in scalar segments), where as the others, like the PE
model code and the Jacobian Operator program, contain several kernels that
lend themselves very well to vectorizing. Additionally, the latter two
codes also contain numerous linked triad operations (e.g., D = A*B + C).
Again, it should be reiterated that this benchmark suite is dominated by
floating-point-intensive codes; therefore, it is NOT intended to reflect
on other measures of CPU performance (like I/O, integer, etc.).

   			Relative Performance in MicroVAX Units
   			======================================

   	      Shallow  Spectral    QG    Multi-   Jacobian  Onelevel  Geom. Mean
              water    model      model  level    operator  channel
     	      model                      PE model           model.
==============================================================================

Cray-YMP	936.0	114.5	 120.4	1155.4	  2196.5   354.1     475.8
Cray-2		784.0	 79.7	  92.5   790.5	  1098.2   275.4     333.7
Cray-XMP	549.3	 77.7	  89.3	 442.4	   878.6   165.3     250.1
CYBER 205       126.8	 38.9	  42.8	 272.6	   399.4    65.2     107.0
Stardent GS2000 164.8	 27.5      9.5*  128.0	   366.1    43.5      66.7
Convex C220	109.9	 19.8	  20.8	 105.9	   244.1    45.9      61.4
IBM RS6000/320   48.5	 30.8	  38.0	  75.8	    81.4    42.7      49.6
Stardent GS1000 103.0	  7.0	   6.9	  67.3	   122.0    18.0      30.0
DECstation 5000  43.4	 17.3	  38.6	  41.6	    22.1    25.0      29.6
Apollo DN10000   53.2	  9.8	  41.4	  29.5	    23.2    33.0      28.0
Silicon Gr 4D/25 32.6    10.1*    29.3    25.7      22.9    15.8      21.1
DECstation 3100	 28.4	 10.0	  25.5	  24.7	    22.1    16.2      20.9
HP 9000/835	 16.7	  7.9	  16.3	  16.6	    18.3     9.7      13.6
Sparcstation 1	 12.6	  4.6	  10.3	  16.0	    11.6     8.7       9.9
MicroVAX II    	  1.0	  1.0	   1.0	   1.0 	     1.0     1.0       1.0

============================================================================
*Could not run at the highest optimization level.
Cray and Convex timings were obtained using just one processor.