Re: [Starpu-devel] [daxpy with StarPU-MPI]

[Nathalie Furmento <nathalie.furmento@labri.fr>]

That would be helpful, i intended to do it to have another example testing 
the collective operations.

Thanks,

Nathalie

On oct. 17, 15:56, Maxim Abalenkov wrote:
> Hello Nathalie,
> 
> False alarm. I have got it working on a Mac too. There was an error related 
> to saving the vector segments into files.
> 
> Maybe, I can contribute this example to the StarPU-MPI examples collection 
> in the Git repository?
> 
> —
> Best wishes,
> Maxim
> 
> Maxim Abalenkov \\ maxim.abalenkov@gmail.com
> +44 7 486 486 505 \\ http://mabalenk.gitlab.io
> 
> > On 17 Oct 2018, at 15:51, Maxim Abalenkov <maxim.abalenkov@gmail.com> 
> > wrote:
> > 
> > Dear Nathalie,
> > 
> > Thank you very much for your help. I have corrected the mistakes you 
> > noticed. The code runs and computes the result correctly on Linux. 
> > However, it still crashes with the SIGABRT error on Mac. Please find the 
> > debug log attached. Unfortunately, I can’t get a more meaningful output 
> > from it.
> > 
> > —
> > Best wishes,
> > Maxim
> > 
> > <daxpy_mpi.c>
> > <daxpy_mpi.h>
> > <gdb.log>
> > <Makefile>
> > <tst_daxpy_mpi.c>
> > 
> > Maxim Abalenkov \\ maxim.abalenkov@gmail.com 
> > <mailto:maxim.abalenkov@gmail.com>
> > +44 7 486 486 505 \\ http://mabalenk.gitlab.io 
> > <http://mabalenk.gitlab.io/>
> > 
> >> On 17 Oct 2018, at 14:09, Nathalie Furmento <nathalie.furmento@labri.fr 
> >> <mailto:nathalie.furmento@labri.fr>> wrote:
> >> 
> >> Here some mistakes i found in your code.
> >> 
> >> * when allocating hx and hy, you should specify 
> >> sizeof(starpu_data_handle_t) and not sizeof(starpu_data_handle_t*)
> >> 
> >> // allocate data handles
> >> starpu_data_handle_t *hx = (starpu_data_handle_t *) 
> >> malloc((size_t)NT*sizeof(starpu_data_handle_t));
> >> starpu_data_handle_t *hy = (starpu_data_handle_t *) 
> >> malloc((size_t)NT*sizeof(starpu_data_handle_t));
> >> 
> >> * you need to check if hx[i] and hy[i] are valid before calling 
> >> starpu_data_unregister()
> >> 
> >> // unregister vector handles
> >> for (int i = 0; i < NT; i++)
> >> {
> >>    if (hx[i]) starpu_data_unregister(hx[i]);
> >>    if (hy[i]) starpu_data_unregister(hy[i]);
> >> }
> >> 
> >> Everything else seems ok, let us know if it keeps failing, and more 
> >> important, a backtrace of your segfault would be really useful. We 
> >> cannot guess otherwise how it fails.
> >> 
> >> Cheers,
> >> 
> >> Nathalie
> >> 
> >> On oct. 17, 12:54, Maxim Abalenkov wrote:
> >>> Dear Samuel et al.,
> >>> 
> >>> I hope all is well with you. Would you please be so kind to check the 
> >>> logic of my StarPU-MPI “daxpy” code? I’m following the Handbook code 
> >>> snippet on StarPU-MPI. I use two vectors x, y of length N=10 split into 
> >>> NT=5 segments nb=2 elements each. Running on a single processor with 
> >>> mpiexec -np 1 ./tst_daxpy_mpi the first three segments are calculated 
> >>> correctly, while the last two are unchanged. It seems there is a 
> >>> synchronisation issue. In case I launch the code on two CPUs it crashes 
> >>> with a segmentation fault. Thank you and have a good day ahead!
> >>> 
> >>> —
> > 
> 

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Dr Nathalie Furmento                         Ingénieure de recherche CNRS
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