Re: Performance on new 64bit server compared to my 32bit desktop

Hi!

On Tue, Aug 31, 2010 at 8:11 AM, Yeb Havinga <yebhavinga(at)gmail(dot)com> wrote:
> Greg Smith wrote:
>>
>> Yeb Havinga wrote:
>>>
>>> model name      : AMD Phenom(tm) II X4 940 Processor @ 3.00GHz
>>> cpu cores         : 4
>>> stream compiled with -O3
>>> Function      Rate (MB/s)   Avg time     Min time     Max time
>>> Triad:       5395.1815       0.0089       0.0089       0.0089
>>
>> I'm not sure if Yeb's stream was compiled to use MPI correctly though,
>> because I'm not seeing "Number of Threads" in his results.  Here's what
>> works for me:
>>
>>  gcc -O3 -fopenmp stream.c -o stream
>>
>> And then you can set:
>>
>> export OMP_NUM_THREADS=4
>
> Then I get the following. The rather wierd dip at 5 threads is consistent
> over multiple tries:
>
> Number of Threads requested = 1
> Function      Rate (MB/s)   Avg time     Min time     Max time
> Triad:       5378.7495       0.0089       0.0089       0.0090
>
> Number of Threads requested = 2
> Function      Rate (MB/s)   Avg time     Min time     Max time
> Triad:       6596.1140       0.0073       0.0073       0.0073
>
> Number of Threads requested = 3
> Function      Rate (MB/s)   Avg time     Min time     Max time
> Triad:       7033.9806       0.0069       0.0068       0.0069
>
> Number of Threads requested = 4
> Function      Rate (MB/s)   Avg time     Min time     Max time
> Triad:       7007.2950       0.0069       0.0069       0.0069
>
> Number of Threads requested = 5
> Function      Rate (MB/s)   Avg time     Min time     Max time
> Triad:       6553.8133       0.0074       0.0073       0.0074
>
> Number of Threads requested = 6
> Function      Rate (MB/s)   Avg time     Min time     Max time
> Triad:       6803.6427       0.0071       0.0071       0.0071
>
> Number of Threads requested = 7
> Function      Rate (MB/s)   Avg time     Min time     Max time
> Triad:       6895.6909       0.0070       0.0070       0.0071
>
> Number of Threads requested = 8
> Function      Rate (MB/s)   Avg time     Min time     Max time
> Triad:       6931.3018       0.0069       0.0069       0.0070
>
> Other info: DDR2 800MHz ECC memory

Ok, this could explain the huge difference. I was planing on getting
GigaByte GA-890GPA-UD3H, with a Phenom II X6 and that ram: Crucial
CT2KIT25664BA13​39, Crucial BL2KIT25664FN1608, or something better I
find when I get enough money (depending on my budget at the moment).

> MB: 790FX chipset (Asus m4a78-e)
>
> regards,
> Yeb Havinga
>
>

Thanks for the extra info!

Ildefonso.