Re: How are CPU Speed and Overall CPW Related? -- MIDRANGE-L

> From: Jon.Paris@hal.it

> Nathan, while I doubt it will erase all of the time difference, the
> code in your example is not doing anything like the same thing.

Take a second look at the code, Jon.  Both programs trim a <variable>
containing exactly 50 bytes (39 of which are blank), then assign the result
to another variable.  alltrim() is equivalent to %trim().  Also consider
that Foxpro is an interpreted language, while the RPG code was
compiled with OPTIMIZE = *FULL.

> None of this matters worth a darn though because real programs
> don't simply wizz round in circles doing nothing.

The intent was not to test a mixed workload.  Only to compare CPU
performance.  Sure there are many other factors to consider, but I still
think CPU performance is "worth a darn".  The test showed the Intel CPU to
have much higher throughput.  Is that not the reason Intel servers are so
prevalent?  I don't believe it's due to the merits of Windows.  I believe
the AS/400 CPU is artificially bridled by limited cache.  My simple logic
says take off the artificial constraint, and let the CPU do more work -
Particularly CPU intensive Web and client-server work.  Instead of watch
"win-tel" take over the server market.

> From: Pat Barber <mboceanside@worldnet.att.net>

> Since the 400 is task interrupt driven, it attempts to service
> all tasks that it has been given in a reasonable amount of time.
> It does not have just one single task of run these 30 or so
> instructions and "then" go check to see how everybody else
> is doing. Every single job in the system gets a whack at the
> processor but that schedule is a fairly complicated process
> that requires time.

It might invalidate the test if OS/400 were doing more work than Windows
during the test, but I don't believe this to be the case.  I still think the
programs test CPU throughput with a sufficiently valid degree of accuracy.

Here's something more meaningful:

I recently sent the RPG source to another list participant who compiled and

ran the program on his 170-2385.  The program ran 11 times faster.  The main
difference between his system and my 170-2290 is 4MB of L2 cache.  That
really supports my hypothesis that a cache constraint artificially restricts
the CPU.  I actually don't know how much cache the 170-2290 has.  That
information is not published.  Part of that obfuscation I mentioned earlier.

Nathan.




+---
| This is the Midrange System Mailing List!
| To submit a new message, send your mail to MIDRANGE-L@midrange.com.
| To subscribe to this list send email to MIDRANGE-L-SUB@midrange.com.
| To unsubscribe from this list send email to MIDRANGE-L-UNSUB@midrange.com.
| Questions should be directed to the list owner/operator: david@midrange.com
+---