Re: [Starpu-devel] Question about MPI usage

[Xavier Lacoste <xl64100@gmail.com>]

Nathalie,

Thanks for your fast answer, I forgot what was this parameter for when I 
copy/paste the registering code.

Sorry, should have read the manual again ;)

XL.

Le 31 janv. 2014 à 10:50, Nathalie Furmento <nathalie.furmento@labri.fr> a 
écrit :

> Xavier,
> 
> When you want to register a data that will be allocated only when it is 
> used for the first time, you need to set the "home node", the 2nd parameter 
> of starpu_xxx_data_register to -1.
> 
> Cheers,
> 
> Nathalie
> 
> On 31/01/2014 10:46, Xavier Lacoste wrote:
>> Hi,
>> 
>> I'm porting PaStiX multicore StarPU code to MPI StarPU.
>> I register on each node local data and halo data (data that willl be read 
>> used to update local data or that will be updated using local data).
>> halo data is registered using NULL pointer :
>> 
>>     starpu_matrix_data_register(&(Lhalo_handle[itercblk]), 0,
>>                                 (uintptr_t)NULL,
>>                                 (uint32_t)HCBLK_STRIDE(itercblk),
>>                                 (uint32_t)HCBLK_STRIDE(itercblk),
>>                                 HCBLK_COLNBR(itercblk),
>>                                 sizeof(PASTIX_FLOAT));
>>     starpu_data_set_rank(Lhalo_handle[itercblk], HCBLK_OWNER(itercblk));
>>     starpu_data_set_tag(Lhalo_handle[itercblk],  HCBLK_GCBLK(itercblk));
>> 
>> On the proc that possess the data, the same data is registered with an 
>> allocated area (same owner/tag) :
>> 
>>     starpu_matrix_data_register(&(L_handle[itercblk]), 0,
>>                                 (uintptr_t)SOLV_COEFTAB(itercblk),
>>                                 (uint32_t)SOLV_STRIDE(itercblk),
>>                                 (uint32_t)SOLV_STRIDE(itercblk),
>>                                 CBLK_COLNBR(itercblk),
>>                                 sizeof(PASTIX_FLOAT));
>>     starpu_data_set_rank(L_handle[itercblk], SOLV_PROCNUM);
>>     starpu_data_set_tag(L_handle[itercblk], UPDOWN_LOC2GLOB(itercblk));
>> 
>> When some tasks are submitted i get this error :
>> 
>> [starpu][_starpu_mpi_irecv_data_func][assert failure] Invalid pointer to 
>> receive data
>> 
>> simple: starpu_mpi.c:487: _starpu_mpi_irecv_data_func: Assertion 
>> `req->ptr' failed.
>> 
>> When I look into starpu_mpi.c:1422 i found that it is due to 
>> starpu_data_get_local_ptr() returns a NULL pointer:
>> 
>>                                         if (found_req->user_datatype == 0)
>>                                         {
>>                                                 found_req->count = 1;
>>                                                 found_req->ptr = 
>> starpu_data_get_local_ptr(found_req->data_handle);
>>                                                 fprintf(stdout, "%s:%d 
>> found_req->ptr %p\n", __FILE__, __LINE__, found_req->ptr);
>>                                         }
>> 
>> I'm certainly doing an error somewhere, do you have any clue ? Is this the 
>> NULL pointer i'm giving to starpu_matrix_data_register() ?
>> I don't want to allocate this halo data before i need it... It should only 
>> update my local data and be deleted, I was hopping that StarPU was going 
>> to do that...
>> 
>> Any Idea of what I'm doing wrong ?
>> 
>> Regards,
>> 
>> XL.
>> 
>> PS: As we already gave all informations to starpu_mpi_task_build(), 
>> wouldn't it be possible to only give the task to 
>> starpu_mpi_task_post_build() ? That would make the code lighter :)
>> _______________________________________________
>> Starpu-devel mailing list
>> Starpu-devel@lists.gforge.inria.fr
>> http://lists.gforge.inria.fr/cgi-bin/mailman/listinfo/starpu-devel
>