program not scalable

[Liu, Jaln]

Hi,

I use the PnetCDF to read a 4D dataset, the size is around 4G. I found the program is not scalable no matter how I distribute the data.
e.g., I parallelize the program along the time dimension(which is the outer loop/the slowest dimension). The read time is the slowest when only one core is used. The data are striped on multiple storage nodes.

Can anybody help me with that? thanks in advance.


Best Regards,
Jialin Liu, Ph.D student.
Computer Science Department
Texas Tech University
Phone: 806.742.3513(x241)
Office:Engineer Center 304
http://myweb.ttu.edu/jialliu/
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