pnetcdf performance question

[David Wong]

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

I wonder what did I do wrong to have such terrible performance. pnetcdf 
was installed by our SA and the system folks told me that in the I/O 
subsystem, there are only two I/o channel. Does this have anything to do 
with the performance? Your advise/comment/suggestion is appreciated.

Thanks,
David


-- 
David C. Wong Ph.D.
Atmospheric Modeling Division
National Exposure Research Laboratory
US Environmental Protection Agency
Mail Drop E243-03
109 T. W. Alexander Dr.
Research Triangle Park, NC 27711
919-541-3400 919-541-1379 (fax)