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NOTICE: This version of the NSF Unidata web site (archive.unidata.ucar.edu) is no longer being updated.
Current content can be found at unidata.ucar.edu.
To learn about what's going on, see About the Archive Site.
On Tue, Jan 15, 2013 at 03:55:44PM -0500, Ben wrote: > Does anyone have any tricks I haven't thought of or has seen the > same thing with parallel IO performance? There really aren't that > many things one can play with other than setting the MPI hints or > changing the access type for variables (collective or independent). > So far I have been using intel 11, intel mpi 3 on the gpfs file > system but I plan to play with this on newer intel versions, > different MPI stacks, and on lustre instead of gpfs. You are probably seeing an interaction between GPFS and MPI-IO. Inten MPI 3 isn't, to my knowledge, particularly tuned to GPFS. Fortunately the one tuning step that helps GPFS is to align "file domains". Set the "striping_unit" hint to the size of your GPFS file system block size. (you can get that with the 'stat -f' command line tool: hopefully it's something like 4 MiB). So, set "striping_unit" to "4194304" and let me know if that helps. ==rob -- Rob Latham Mathematics and Computer Science Division Argonne National Lab, IL USA
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