[netCDF #ABG-853837]: Performance issues with unbalanced load

Hi Sebastian,

> I recently stumbled across a performance problem when using netCDF +
> HDF5 + (Collective) MPI I/O:
> 
> If the application has a great I/O load imbalance (some processes
> reading only a few values while others read several thousand values) I
> get a dramatic performance decrease on our GPFS file system.
> 
> Reading several thousand values with all processes is done within
> seconds. However as soon as I introduce the load imbalance, it takes
> several minutes.
> 
> Anybody experiences the same problems? Any advices?

We haven't seen this problem reported before, but I've forwarded your
question to another developer who has more parallel I/O expertise than
we do at Unidata.  Either he or I will let you know if we come up with
anything that might help ...

--Russ

Russ Rew                                         UCAR Unidata Program
address@hidden                      http://www.unidata.ucar.edu



Ticket Details
===================
Ticket ID: ABG-853837
Department: Support netCDF
Priority: Normal
Status: Closed