Re: Cycles per ASM instruction

Gerard Schildberger wrote:
[snip]
> 
> Here is a very old chart showing some older 360/370 models:
> 
> 
> +---------------------------------------------+----------+
> |            CPU                     family   |  approx. |
> |  vendor    model                 model name |   MIPS   |
> +---------------------------------------------+----------+
> |                                             |          |
> |   IBM      2020                   360/20    |      .02 |
> |   IBM      2022                   360/22    |      .02 |
> |   IBM      2030                   360/30    |      .04 |
> |   IBM      2040                   360/40    |      .09 |
> |   IBM      2044                   360/44    |      .09 |
> |   IBM      2050                   360/50    |      .19 |
> |   IBM      2065                   360/65    |      .70 |
> |   IBMrpq   2067                   360/67    |      .98 |
> |   IBMrpq   2067 mp                360/67    |     1.96 |
> |   IBM      2075                   360/75    |      .89 |
> |   IBM      2085-1                 360/85    |     1.92 |
> |   IBM      2085-2                 360/85    |     2.40 |
> |   IBM      2090                   360/90    |     5.00 |
> |   IBM      2091                   360/91    |     5.00 |
> |   IBM      2092                   360/92    |     5.00 |
> |   IBM      2095                   360/95    |     5.00 |
> |                                             |          |
> +---------------------------------------------+----------+
[snip]
Something wrong here.  No way a /67 could do .98 MIPs.  Nor could a 
/67MP do almost 2 MIPs - the shared memory really slowed that class of 
machine down.  /67s with the DAT turned off were roughly the same as a 
/65; the DAT took about 20% off that.  /67MPs were about 1.75 times the
UP.

A 360/20-5 might make .02 MIPs, but the more common /20s, like the -2, 
were a fraction of that.