[mpich-discuss] ROMIO: 2 phase IO method and error handling

[Rajeev Thakur]

How about reporting the amount of data that actually gets copied into the user buffer. That can be kept track of locally.

Rajeev


On Sep 1, 2010, at 12:40 PM, Rob Latham wrote:

> On Mon, Aug 23, 2010 at 04:35:36PM +0200, Pascal Deveze wrote:
>> I discovered that I can read after the end of file !
>> 
>> After a look in the romio source code, I see that the "2 phase IO"
>> method for read:
>> 1) Does not return the right count value in the status
> ...
>> Has anybody an idea on how to correct this ?
> 
> well, i've got an idea but it's not great.
> 
> We could report how much data each process actually read, but that
> would return surprising results in this test: rank 0 reads 5 bytes but
> rank 1 reads none. 
> 
> So we have to communicate the fact that we had a short read.  I guess
> another allreduce in the collective I/O path won't be so bad, but I
> still need to think some more about how to react to the fact that one
> aggregator had a short read.
> 
> ==rob
> 
> -- 
> Rob Latham
> Mathematics and Computer Science Division
> Argonne National Lab, IL USA
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