[mpas-developers] COMMIT CHECK BUG FIX: MPI timing issue

[Doug Jacobsen]

This is a bit later than I had hoped to originally have this done. But
anyway.....

I have tested this module with gnu, intel, and pgi compilers and it seems
to fix the problem for all of them.

So, unless anyone has any issues with me committing it, I'll push it onto
the trunk tomorrow.

Thanks,
Doug

On Wed, Jun 27, 2012 at 2:14 PM, Doug Jacobsen
<jacobsen.douglas at gmail.com>wrote:

> Hi all,
>
> Recently I have been noticing some weird behavior from MPI_Wtime and
> MPI_Wtick in MPAS, and I think I have a solution for the problem.
>
> After a simple simulation on either my laptop of the IC machines here
> (using gfortran and openmpi or mvapich) I was noticing the timers were all
> 0.0. After that I started writing out what MPI_Wtime and MPI_WTick returned
> to see what the timer should be computed with, and I got values like
>
> MPI_WTime = 3.07144143222521536682484349811465461E-4947
> MPI_WTick  = 2.92504975975246619939945495478118484E-4947
>
> Which are obviously incorrect. The probably apparently has something to do
> with the mpi headers that are being used. So, I made some modifications to
> the modules that are used within mpas_timer.F that fix this problem on my
> end. I'm going to test it some more on the IC machines here with different
> compilers, but I wanted to see if anyone else has problems with my
> modifications or if they break anything.
>
> I have attached a modified version of mpas_timer.F that fixes the issue
> for me, so please let me know if it causes you any issues.
>
> If I don't hear from anyone, I'll push this change onto the trunk on
> Friday.
>
> Thanks,
> Doug
>
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