[Ncep.list.nems.announce] Comments Requested: Moving FMS out of MOM6 and FV3 repos
Vijay Tallapragada (NOAA Federal)
vijay.tallapragada at noaa.gov
Wed Sep 5 21:32:11 UTC 2018
Sam,
I am forwarding this e-mail thread to Rusty Benson with a request to
provide his comments and suggested solutions.
Rusty - please see below and provide your response at your earliest
convenience.
Thanks,
Vijay
On 9/5/2018 1:38 PM, Samuel Trahan - NOAA Affiliate wrote:
> Hi all,
>
> Apologies; there was an ambiguity in my last email. The exact
> contents of the FMS are not decided yet. All that is certain is that
> the FMS will reside in its own repository, and be at the NEMS
> application level. I'm hoping to have a solution within the next few
> days, but it is largely outside my control.
>
> Sincerely,
> Sam Trahan
>
> On Wed, Sep 5, 2018 at 1:36 PM, Samuel Trahan - NOAA Affiliate
> <samuel.trahan at noaa.gov <mailto:samuel.trahan at noaa.gov>> wrote:
>
> Hi all,
>
> We are still awaiting a management decision on how the FMS will be
> handled in NEMS applications. The "FMS component" commit will go
> in, in its current form, but I don't know yet where the FMS will
> reside.
>
> Sincerely,
> Sam Trahan
>
> On Wed, Aug 29, 2018 at 1:00 PM, Samuel Trahan - NOAA Affiliate
> <samuel.trahan at noaa.gov <mailto:samuel.trahan at noaa.gov>> wrote:
>
> Hi all,
>
> We're close to having a solution to the aforementioned
> problem. The details are uncertain at this time, but we'll
> have some kind of joint EMC-DTC fork of FMS in github. It
> will track the GFDL FMS as closely as possible, while making
> it portable enough to use on all RDHPCS machines and common
> clusters elsewhere. The NEMS applications will point to the
> EMC-DTC fork. Management is ruminating on details like
> exactly where it will be, the choice of code manager, the
> commit process, and how the changes are sent back to GFDL; we
> expect to have a solution soon. These may sound like mundane
> details, but having a poor code management process causes
> major problems if it goes on for too long.
>
> The commit will go in soon, but it may be slightly later than
> intended. We'll still try to get it in by Wednesday
> afternoon, but it may be later in the week if decisions on
> code management practices take a lot more discussion time. We
> do expect the commit to be in by the end of next week though.
>
> I'll send out another update when I have more information.
>
> Sincerely,
> Sam Trahan
>
> On Mon, Aug 27, 2018 at 9:47 PM, Samuel Trahan - NOAA
> Affiliate <samuel.trahan at noaa.gov
> <mailto:samuel.trahan at noaa.gov>> wrote:
>
> Hi all,
>
> We have a proposed commit that is urgently needed, but may
> have major negative impacts to a lot of users. Please
> read this email and comment. Our comment period ends at
> noon Tuesday, September 4. The commit, if accepted, will
> happen Wednesday, September 5.
>
> *The Commit: Overview*
>
> In NEMS apps, the FMS exists within both the FV3 and MOM6
> repositories; hence some apps have two copies of FMS. We
> have a proposed commit that will move the FMS up one level
> so there is only one FMS per app. The FMS we've chosen is
> the one from the GFDL repository. The technical details
> of the changes, are largely inconsequential; the main
> issue is the choice of repositories.
>
> *Consequences*
>
> These are the consequences of choosing GFDL's FMS repository.
>
> 1. Portability changes to the FMS will be lost permanently
> because GFDL rejected them. This means the FV3 GFS will
> not be usable except with certain versions of the Intel
> compiler. This has been confirmed.
>
> 2. Recent and upcoming FMS bug fixes will be lost because
> they are not in the GFDL repository.
>
> 3. In general, any FV3 changes will have to wait several
> weeks if they need changes to FMS.
>
> Items #2 and #3 are unavoidable. GFDL FMS has a large
> userbase and lengthy test process. They will, out of
> necessity, have a long delay before commits.
>
> *Alternatives*
>
> I know of three alternatives to our FMS repository
> problem. Any of these may require funding or tasking
> changes, in or from NOAA:
>
> 1. GFDL handles the FV3 GFS as a special case, maintaining
> a branch of FMS for the FV3 GFS, and applying changes
> within 2-3 days. GFDL ports FMS to other compilers.
>
> 2. DTC maintains a fork of FMS which all NEMS apps use.
> DTC maintains any portability changes and regularly pulls
> changes from GFDL FMS. They receive any changes needed
> for NEMS coupling and resolve conflicts as needed.
>
> 3. EMC maintains the aforementioned fork.
>
> Note that DTC is presently tasked with porting the FMS,
> and has successfully ported it to other platforms and
> maintained an FMS repository.
>
> *The Branches*
>
> The changes can be found in the "fms-component" branches
> of the NEMSfv3gfs and EMC_FV3-MOM6-CICE5 repositories.
> These will be updated later this week when incoming FV3
> changes are available. We will be sure to test before
> committing to the relevant branches.
>
> When testing this yourself, note that
> the EMC_FV3-MOM6-CICE5 warm start test will not reliably
> reproduce itself; this is a known issue that is unrelated
> to this commit. Jet baselines are out-of-date, so you
> cannot test there. All other tests should pass for both
> apps on all supported platforms.
>
> *The Commit: Details*
>
> Overview of the changes:
>
> 1. FMS is removed from the build system in MOM6 and FV3
>
> 2. FMS is added at the app level from
> git://github.com/NOAA-GFDL/FMS
> <http://github.com/NOAA-GFDL/FMS>. The "git" url makes
> this submodule read-only. That is a workaround for
> problems in the installation of "git" on WCOSS Cray and
> Dell which make github unreachable via https. This "git"
> installation problem has been a known issue for several
> months and remains unresolved, so such a workaround is
> necessary.
>
> 3. The FMS/fv3gfs directory is updated to be able to build
> FMS outside of FV3. This change was accepted by GFDL in
> their repository.
>
> 4. The NEMSAppBuilder is updated to build FMS. It is
> treated the same way as a coupled component in the build
> system.
>
> 5. Any appBuilder files must include FMS before FV3 or
> MOM6 in their component list.
>
> 6. The NEMSfv3gfs tests/compile.sh is updated to build FMS
> before FV3.
>
> Sincerely,
> Sam Trahan
>
>
>
>
>
>
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--
Vijay Tallapragada, Ph.D.
Chief, Modeling and Data Assimilation Branch
Environmental Modeling Center, NOAA/NWS/NCEP
+1-301-683-3672 (O); +1-202-679-5629 (C)
Vijay.Tallapragada at noaa.gov
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