Re: Multiple processors

[Larry Bolhuis <lbolhuis@xxxxxxxxxx>]

'Under the covers' there is other stuff going on. Having a second 
processor may not cut the time in half but it will help if processor is 
the issue. Maybe only another 0.5 processor can be added before 
diminishing returns are hit but currently there is not sufficient 
information.

Nonetheless others have pointed out that it could be disk or memory 
issues and not processor. Investigation needs to happen and the 
*appropriate* resources brought to bear.

- Larry

Wilt, Charles wrote:
> Justin, are you sure about that?
>
> If this partition really only runs the one job, as the OP said, and the
> system CPU is at ++++.  Then would adding another processor help?  I
> don't believe that the iSeries can spilt a single job between 2
> processors, a jobs only runs on one processor at a time right?
>
> With just a single job involved, the most work you can get is a single
> physical CPU's work of work.
>
> Is he currently getting a physical CPU's worth of work?  Given that the
> OP is talking about partitions, he'd need to look at his partition setup
> since with partitions you're dealing with physical and virtual
> partitions.
>
> If the OP has a single physical CPU assigned to the partition, and that
> CPU is being maxed out on this one job; the only way to get more work
> would be too add CPU(s) AND split the job into multiple jobs.
>
> Splitting the job could be very easy.  For example, if the job reads
> from record #1 to record #1,000,000 split it into 2 jobs one that
> handles records 1-500,000 the other handles 500,001 to 1,000,000.
> Assuming a 2 CPU system and storage subsystem that can support it,
> you'll get done in half the time.
>
> I remember reading an article, I think from the IBM teraplex Center,
> that discussed this method of improving batch jobs.  
>
> Lastly, when looking at the DASD subsystem, we need to know if the job
> uses journal files and rather or not it uses commitment control.
>
> HTH,
>
> Charles Wilt
> --
> iSeries Systems Administrator / Developer
> Mitsubishi Electric Automotive America
> ph: 513-573-4343
> fax: 513-398-1121
>   
>