[MITgcm-devel] missing barrier causing problems for packing

[Jean-Michel Campin]

Hi Matt,

I don't feel qualified to answer your question. 
Patrick, please, help !

Cheers,
Jean-Michel

On Mon, Jan 30, 2012 at 04:20:09PM -0800, Matthew Mazloff wrote:
> Hi Jean-Michel
> 
> Yes, an MPI_BARRIER call, thanks for clarifying.
> 
> And at the top of CTRL_PACK would be a great place for it.  Would it
> be ok for me to check this in -- does anyone have any objections?
> 
> An alternative fix would be to pack the ctrls first, then the
> gradients.....
> 
> let me know, thanks
> -Matt
> 
> 
> 
> 
> 
> On Jan 30, 2012, at 4:05 PM, Jean-Michel Campin wrote:
> 
> >Hi Matt,
> >
> >Just to clarify a detail: you mean an MPI_BARRIER call
> >(the usual _BARRIER just sync threads and does not do anything
> >between different MPI procs).
> >
> >There is an example of such a call in ini_procs.F
> >(the one in eeboot_minimal.F is not the right one)
> >
> >And as where to put it, may be (naively) at the top of S/R CTRL_PACK ?
> >
> >Cheers,
> >Jean-Michel
> >
> >On Mon, Jan 30, 2012 at 02:13:19PM -0800, Matthew Mazloff wrote:
> >>Hello
> >>
> >>We have come across the problem where the packing initiates before
> >>all processors finish writing adxx_theta, and thus sometimes
> >>ecco_cost is incorrect (zeros were read/written instead of proper
> >>gradients.)
> >>
> >>We need to have a barrier put in either
> >>
> >>around line 261 at the beginning of the_main_loop.F before
> >>CALL INITIALISE_VARIA( mythid )
> >>
> >>or in the_model_main.F  around line 600 between
> >>     CALL THE_MAIN_LOOP( myCurrentTime, myCurrentIter, myThid )
> >>and
> >>        CALL CTRL_PACK( .FALSE. , mythid )
> >>
> >>
> >>Let me know what is preferable -- and if someone wants to go ahead
> >>and check this in that would be great!
> >>
> >>Thanks
> >>Matt
> >>
> >>
> >>
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> >
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> 
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