pnetcdf performance question

[Robert Latham]

On Mon, Jan 12, 2009 at 08:28:17AM -0500, David Wong wrote:
> Hi,
>
>   I am new to pnetcdf. Recently, I did a small experiment on a SGI Altix 
> machine and here is the performance (in seconds):
>
>      regular     pnetcdf
> 1x1   40513       39954
> 2x1   23325       23418
> 2x2   13021       13198
> 4x2    9734        8542
> 4x4    4578        4751
> 8x4    2810        3342
> 8x8    1821        2755
> 12x8    1445        2426
> 14x8    1372        2599

First, I need a little more help understanding your numbers.  What
does the first collumn mean?  Since time goes down as they get bigger,
I presume you are taking a fixed amount of data and decomposing that
data into a grid of some sort?  But that's just a guess and I'd like
to know for sure.    

Are you reading or writing or both?

Second, how many processors are involved in this operation?  

==rob

-- 
Rob Latham
Mathematics and Computer Science Division    A215 0178 EA2D B059 8CDF
Argonne National Lab, IL USA                 B29D F333 664A 4280 315B