Re: [Starpu-devel] [LU factorisation: gdb debug output]

[Maxim Abalenkov <maxim.abalenkov@gmail.com>]

Hello Samuel,

Thank you for your reply. I believe, I don’t need multiple views. I can pack a collection of tiles before submitting the task and unpack them inside the CPU function. This can be achieved with the StarPU data mode array (Similarly to the fmultiple_manual.c). This is how I’m doing it:

// Create panel data mode array
    struct starpu_data_descr *panel_desc =
        malloc((size_t)A.mt * sizeof(struct starpu_data_descr));

    for (int i = 0; i < A.mt; i++) {
        panel_desc[i].handle = A(i,k);
        panel_desc[i].mode   = STARPU_RW;
    }

    // Enforce task execution on home node (STARPU_MAIN_RAM)
    core_starpu_codelet_zgetrf_pnl.specific_nodes = 1;

    for (int i = 0; i < STARPU_NMAXBUFS; i++) {
        core_starpu_codelet_zgetrf_pnl.nodes[i] = STARPU_MAIN_RAM;
    }

    int retval = starpu_task_insert(
        &core_starpu_codelet_zgetrf_pnl,
        STARPU_VALUE,              &A,                    sizeof(plasma_desc_t),
        STARPU_DATA_MODE_ARRAY,    panel_desc,            A.mt,
        STARPU_W,                  hPiv,
        STARPU_VALUE,              &k,                    sizeof(int),
        STARPU_VALUE,              &nvak,                 sizeof(int),
        STARPU_VALUE,              &ib,                   sizeof(int),
        STARPU_VALUE,              &num_panel_threads,    sizeof(int),
        STARPU_VALUE,              sequence,              sizeof(plasma_sequence_t),
        STARPU_VALUE,              request,               sizeof(plasma_request_t),
        STARPU_NAME,              "zgetrf_pnl",
        0);

    STARPU_CHECK_RETURN_VALUE(retval, "core_starpu_zgetrf_pnl: starpu_task_insert() failed”);

My only problem is to unpack the tiles and the pivots vector together, one after another inside the CPU kernel function. I can’t achieve this. Thank you.

—

Best wishes,

Maxim

Maxim Abalenkov \\ maxim.abalenkov@gmail.com
+44 7 486 486 505 \\ http://mabalenk.gitlab.io

On 28 Dec 2017, at 20:14, Samuel Thibault <samuel.thibault@inria.fr> wrote:

Maxim Abalenkov, on jeu. 28 déc. 2017 19:47:17 +0200, wrote:

Now I remembered another reason, why the multiple views were not suitable for
my application: sometimes I need to specify dependencies on both a panel and a
tile. And that won’t work, since only one view can be active at a time, i.e. if
a panel view is active all the tile handles will be invalid.

You can do either

- synchronization between multiple views by hand, just like
examples/filters/fmultiple_manual.c
- synchronization between multiple views through filters with
explicit submission of synchronization between views, just like
examples/filters/fmultiple_submit.c
- starting with the future StarPU 1.3, synchronization between multiple
views through filtesr with implicit submission, just like
examples/filters/fmultiple_submit_implicit.c

One option I see, is to use a custom data interface to pack/unpack the panel
tiles and the pivots vector.

You do not need specific data interfaces for these: they are still
matrices.

Samuel