Re: 890 cpw per cpu

[John Myers - MM <jmyersmm@xxxxxxxxxx>]

Steve,

There is a certain amount of overhead consumed in managing multiprocessor
systems ... the total CPW rating reflects that overhead.  Doing the
division by 32 gives a per processor total that assumes the overhead and
that each processor is being used at 100% of capacity.

As my Motor Vehicle clients say ... "Your results may vary ...".

A 32 processor system will not be 32 times as fast as a one processor
system ... in a commercial workload, different processors will operate at
different percentages of utilization all the time.  Under OS/400, a job
gets dispatched to one processor, which runs it.  Unless OS/400 has changed
significantly (and I'm very sure that it hasn't), a 32 processor system
will be no faster than a one processor system if only one job is running in
the system.

HTH ... let me know if you are looking for more detail on this.

John

At 02:47 PM 4/29/2002, you wrote:

>The cpw of the new 890 looks to be about 1170 per cpu.  ( 37,400 / 32 ).
>The cpw per processor of the other iSeries models is about 1070  ( cpw of
>the 270/2432 ).  The 890 runs on a 1.3 GHz Power4 processor. The processor
>of the 270 runs at less than half that speed ?
>
>Why is the cpw per cpu of the new 890 not higher ?
>
>Does the power4 processor of the 890 actually run at 1.3 GHz?
>
>Steve Richter
>
>
> >i890 REGATTA SERVER
> >The 32-way i890 nearly doubles the processing power of the i840 to
> >37,400 CPW (see Figure 1 in the online version of this article). The
> >1.3 GHz Power4 chips cram 174 million transistors onto two
> >processors and enable the i890 to crank out transactions so fast
> >that it consumes energy at a breakneck pace, requiring 3-phase power
> >and dissipating up to 25,000 kBTUs of heat per hour.
>
> >The i890 triples the I/O capacity of last year's i840, supporting up
> >to 72 TB of disk, 2,047 disk arms, and 256 GB memory. The machine
> >also connects up to 32 Integrated xSeries Adapters (IXAs) and offers
> >up to 534 MB of L2/L3 cache.
>
>
>--
>
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