Rumour about IBM benchmarks

[jim frost]

david at torsqnt.UUCP (David Haynes) writes:
>I have heard a rumour that the benchmark results that IBM posted for
>their RS6000 system were the results of hand-coded, hand-optimized
>assembler coding rather than the result of compiling C or FORTRAN
>code. Can anyone confirm or deny this? 

This wouldn't be strange practice amongst vendors but I've done some
of my own benchmarks with the RIOS and find that it does just under
three times the raw performance of a sparcstation 1 in the drystone
test.  An IO benchmark I played with showed almost exactly 1mb/sec
write throughput and 8mb/sec read throughput, which is what I would
call `pretty fast'.  The test was designed to negate the effects of
in-memory disk caching (ie it used a large read/write space).  File
creation times weren't particularly fast, though.

Interestingly the machine doesn't `feel' as fast as it tests -- the
one I have here (RS/6000 model 520 w/ 32Mb RAM and all the graphics
hardware I'll ever need) feels more sluggish than a 12Mb sparcstation
running the same kinds of utilities (except things like `grep' which
go quite fast).  I hear that performance becomes much better once you
get more than about 40Mb RAM in the thing so I wonder if there's not a
VM problem.  I won't know until we stuff more memory in it.

While I expect they tuned code to get stellar performance, the numbers
aren't way out of line.  I expect that OS tuning will reduce the
sluggishness I notice -- things don't seem to be very well tuned right
now.

Happy hacking,

jim frost
saber software
jimf at saber.com