Re: [Starpu-devel] Assert : Number of copy requests left is not zero

[Xavier Lacoste <xl64100@gmail.com>]

Le 4 nov. 2014 à 11:11, Samuel Thibault <samuel.thibault@ens-lyon.org> a 
écrit :

> Xavier Lacoste, le Tue 04 Nov 2014 10:49:52 +0100, a écrit :
>>>> [starpu][_starpu_mpi_early_data_check_termination][assert failure] 
>>>> Number of copy requests left is not zero
>>>> 
>>>> Have you get an idea of what could cause this assert ?
>>> 
>>> I have added a note in the message: did you forget to post a receive
>>> corresponding to a send?
>> 
>> Hmm I'll have a look at it.
>> Can it be that I flush a data earlier than it should be ?
> 
> Ah, I'm realizing: you are not using starpu_mpi_send, starpu_mpi_recv
> and alike explicitly, and always rely on the communications implicitly
> generated by starpu_mpi_task_insert?
Yes, indeed.
> 
> Normally, if all MPI nodes are doing exactly the same submission loop,
> flushing data earlier is not a problem: the node needing it later will
> receive it again, and the node owning it will know that the node needing
> it later will need it, and thus sending it again.
I'm not doing the same submission loop on all MPI nodes.
I'm inserting only tasks using local data (as I tried to explain in the 
algorithms in my previous mail).
Thus a mistake is possible here in my side.
>  Perhaps there is a
> bug in StarPU-MPI, but we already test this scenario, so I'd rather
> first make sure that the application is really running the same
> submission loop first (perhaps you have made mistakes while pruning the
> submission, and thus the node owning the data doesn't know it has to
> send it again, or conversely).
Yes, I'll check my submission loops.
> 
> Samuel

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