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Subject: Re: [OMPI devel] Duplicated modex issue.
From: Victor Kocheganov (victor.kocheganov_at_[hidden])
Date: 2012-12-20 12:12:41


In every 'modex' block I use coll->id = orte_process_info.peer_modex; id
and in every 'barrier' block I use coll->id = orte_process_info.peer_init_
barrier; id.

P.s. In general (as I wrote in first letter), I use 'modex' term for
following code:
    coll = OBJ_NEW(orte_grpcomm_collective_t);
    coll->id = orte_process_info.peer_modex;
    if (ORTE_SUCCESS != (ret = orte_grpcomm.modex(coll))) {
        error = "orte_grpcomm_modex failed";
        goto error;
    }
    /* wait for modex to complete - this may be moved anywhere in mpi_init
     * so long as it occurs prior to calling a function that needs
     * the modex info!
     */
    while (coll->active) {
        opal_progress(); /* block in progress pending events */
    }
    OBJ_RELEASE(coll);

and 'barrier' for this:

    coll = OBJ_NEW(orte_grpcomm_collective_t);
    coll->id = orte_process_info.peer_init_barrier;
    if (ORTE_SUCCESS != (ret = orte_grpcomm.barrier(coll))) {
        error = "orte_grpcomm_barrier failed";
        goto error;
    }
    /* wait for barrier to complete */
    while (coll->active) {
        opal_progress(); /* block in progress pending events */
    }
    OBJ_RELEASE(coll);

On Thu, Dec 20, 2012 at 8:57 PM, Ralph Castain <rhc_at_[hidden]> wrote:

>
> On Dec 20, 2012, at 8:29 AM, Victor Kocheganov <
> victor.kocheganov_at_[hidden]> wrote:
>
> Thanks for fast answer, Ralph.
>
> In my example I use different collective objects. I mean in every
> mentioned block I call *coll = OBJ_NEW(orte_grpcomm_**collective_t);*
> and *OBJ_RELEASE(coll);* , so all the grpcomm operations use unique
> collective object.
>
>
> How are the procs getting the collective id for those new calls? They all
> have to match
>
>
>
> On Thu, Dec 20, 2012 at 7:48 PM, Ralph Castain <rhc_at_[hidden]> wrote:
>
>> Absolutely it will hang as the collective object passed into any grpcomm
>> operation (modex or barrier) is only allowed to be used once - any attempt
>> to reuse it will fail.
>>
>>
>> On Dec 20, 2012, at 6:57 AM, Victor Kocheganov <
>> victor.kocheganov_at_[hidden]> wrote:
>>
>> Hi.
>>
>> I have an issue with understanding *ompi_mpi_init() *logic. Could you
>> please tell me if you have any guesses about following behavior.
>>
>> I wonder if I understand ringh, there is a block in *ompi_mpi_init() *function
>> for exchanging procs information between processes (denote this block
>> 'modex'):
>>
>> coll = OBJ_NEW(orte_grpcomm_collective_t);
>> coll->id = orte_process_info.peer_modex;
>> if (ORTE_SUCCESS != (ret = orte_grpcomm.modex(coll))) {
>> error = "orte_grpcomm_modex failed";
>> goto error;
>> }
>> /* wait for modex to complete - this may be moved anywhere in mpi_init
>> * so long as it occurs prior to calling a function that needs
>> * the modex info!
>> */
>> while (coll->active) {
>> opal_progress(); /* block in progress pending events */
>> }
>> OBJ_RELEASE(coll);
>>
>> and several instructions after this there is a block for processes
>> synchronization (denote this block 'barrier'):
>>
>> coll = OBJ_NEW(orte_grpcomm_collective_t);
>> coll->id = orte_process_info.peer_init_barrier;
>> if (ORTE_SUCCESS != (ret = orte_grpcomm.barrier(coll))) {
>> error = "orte_grpcomm_barrier failed";
>> goto error;
>> }
>> /* wait for barrier to complete */
>> while (coll->active) {
>> opal_progress(); /* block in progress pending events */
>> }
>> OBJ_RELEASE(coll);
>>
>> So,* *initially* **ompi_mpi_init()* has following structure:
>>
>> ...
>> 'modex' block;
>> ...
>> 'barrier' block;
>> ...
>>
>> I made several experiments with this code and the following one is of
>> interest: if I add sequence of two additional blocks, 'barrier' and
>> 'modex', right after 'modex' block, then* **ompi_mpi_init() *hangs in *
>> opal_progress()* of the last 'modex' block.
>>
>> ...
>> 'modex' block;
>> 'barrier' block;
>> 'modex' block; <- hangs
>> ...
>> 'barrier' block;
>> ...
>>
>> Thanks,
>> Victor Kocheganov.
>> _______________________________________________
>> devel mailing list
>> devel_at_[hidden]
>> http://www.open-mpi.org/mailman/listinfo.cgi/devel
>>
>>
>>
>> _______________________________________________
>> devel mailing list
>> devel_at_[hidden]
>> http://www.open-mpi.org/mailman/listinfo.cgi/devel
>>
>
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