[mpich-discuss] romio large array

[Dave Goodell]

On Apr 25, 2010, at 12:27 PM, burlen wrote:

> I have an array which I like to read into a single process it's  
> 1024x1024x512x4, 2GB, but when I try to read it I get the error
>
> Invalid argument, error stack:
> MPI_FILE_READ_ALL(105): Invalid count argument
>
> In this case count is 536870912 and data type is MPI_FLOAT. Is it  
> possible to read the 2GB array on a single process ? The system has  
> 16 GB per node.


[adding RobL]

It looks like ROMIO is checking for reads of more data than INT_MAX  
bytes in a single call.  I'm guessing that this is defensive because  
some of the internal code in ROMIO may not be prepared to handle this  
case.  Rob can probably comment with less speculation.

The best workaround is probably to split the read into two reads for  
now.

-Dave