I'm confused about one thing.

After reading this, it sounds like your SL43 based machine was running 
on an intel based processor, and your SL44 based machine was running on 
an AMD processor.

If that is the case, you really can't judge anything between these two 
comparisons.

If you want to compare, you have to load SL44 onto the one machine, run 
the tests several times, then load SL43 (in the same configuration) onto 
the same machine.

Or, if you want to compare the hardware, you have to load the same 
configuration (either SL44 or SL43) onto the two different set's of 
hardware.

But to have both different hardware and different software and ask us 
why the numbers are different ... that really doesn't work.

Troy

rochelle lauer wrote:
> 
> 
> ------------------------------------------------------------------------
> 
> Hello,
> 
> I am trying to understand some weird performance characteristics
> on a newly purchased blade (see statistics below).
> 
> The hardware is an HP BL465 with 2 dual core AMD HE 2216 processors.
> This is the first AMD and first 64 processor we have bought.
> 
> I installed SL44 x86_64 and we did some performance tests.
> 
> When running a single job (compute bound monte-carlo with HBOOK output)
> the performance was about twice as slow as running on our
> Intel based blade. Although this difference
> could be attributed to difference in
> proccesors, running several single
> jobs in a row produced rather erratic results...
> 200-300 seconds different on a 900 second job.
> Some were comparable to the 32 bit processor, some were not.
> 
> Also, running 4 of the same jobs in parallel
> produced results which were almost twice as fast !
> 
> I then (for fun) installed SL43 x86_64 .  This produced results
> quite different than those on SL44 and more compatible with
> our 32 bit blades.
> 
> Below  is a sample of the CPU statistics 
> 
> We first ran the existing 32 bit executable.
> 
> We then recompiled and ran the 64 bit executable.
> 
> Many of our jobs cannot be recompiled (won't compile on gcc 3.4 or have
> missing libraries) so we would really like to understand this performance
> discrepency on 32 bit executables and SL44.
> 
> 32 bit executable single job
> 
>      SL 44                          SL43
>        906 sec                       556 sec
>   
> 32 bit executable 4 jobs in parallel
> 
>    SL44                          SL43
> 
> job 1   452 sec                 446 sec
> job 2   446 sec                 442 sec
> job 3   445 sec                 444 sec 
> job 4   448 sec                 446 sec
> 
> 
> 64 bit executable single job
> 
>     510 sec                    497  sec
>     The 64 bit executable seems to be a little more predictable
> 
> 
> So, does anyone  have any idea 
> 
>   1. Why such a difference in performance between SL44 and SL43 (Why does
>      SL44 produce much slower results on a single job)
> 
>   2. Why running 4 jobs in parallel produces faster results than
>       a single job ? One would think jobs running in parallel
>       would produce slightly slower performance.
> 
>   3. Why running 4 jobs in parallel on SL44 produces much
>      faster results (900 sec vs 452 sec) .
> 
>   4. Should we not be running our 32 bit executables with an
>      SLxx  x86_64  installed ?
>      I have not yet tried installing SL44(43) x86 to check the
>      performance. Should I ?
>     
> 
> 
> 
> Thanks for any insight or help
> 
> Regards
> Rochelle Lauer
> Yale University Physics
> 


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Troy Dawson  [log in to unmask]  (630)840-6468
Fermilab  ComputingDivision/LCSI/CSI DSS Group
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