[mpich2-dev] MPI_File_get_position_shared scaling

[Bob Cernohous]

We have a customer complaint that:

"The MPI subroutine MPI_File_get_position_shared is too slow and has a bad 
 impact on I/O performance. "

>From what I can see, each rank exclusively locks and operates on the 
shared_fp.  So it doesn't scale well, but I don't see anything BlueGene 
specific.  Am I missing an ad_xxx that does something better?  Or is this 
just "as expected".  Any comments from the ROMIO experts?

Bob Cernohous:  (T/L 553) 507-253-6093

BobC at us.ibm.com
IBM Rochester, Building 030-2(C335), Department 61L
3605 Hwy 52 North, Rochester,  MN 55901-7829

> Chaos reigns within.
> Reflect, repent, and reboot.
> Order shall return.
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