11 March
Pearse, Anton, Ezhil, Noah, Chris, Siobhan, Manodeep, Helen, Andrew K, Dougie
WOMBATlite performance - what to do about OM2 configurations?
- OM2 with WOMBATlite is slower than legacy WOMBAT
- see Add `dev-01deg_jra55_ryf+wombatlite` configuration by dougiesquire · Pull Request #286 · ACCESS-NRI/access-om2-configs · GitHub for numbers
- Now so slow at 0.1 degree that it doesn’t complete 1 month in max walltime (5 hours)
- Wombatlite has 5 more tracers than legacy WOMBAT
- Both the calculations in Wombatlite and addition of tracers slow the model down.
Om3 doesn’t have this problem as it has the long tracer timestep
Dougie suggests Sapphire Rapids and increasing ocean core count - will plan to implement for all BGC configs.
Pearse suggests removing two DIC tracers
Pearse is planning at least one IAF cycle of 0.25 degree. And longer “spinups” with 1 degree
Then some targetted research using 0.1 degree and possibly do an updated control run with this.
WOMBATlite is fairly mature - ready for some memory / loop optimisation work
Global metrics
CICE consortium are having some preliminary discussions about a refactor of the history code. The question came up about whether to include hemispherical scalars
In OM2 - the global metrics was very slow to calculate. Therefore using snaphsots to reduce the number of global gathers.
We would use but probably not a great tool for science - medium priority
OM3 - Next deployment
For the IAF cycle this month - we need at least WOMBATlite updated
Access3-share - the coupler (CMEPS / CDEPS and share) components have been updated
CICE/WW3 yet to be updated, but possibly could be monday. ADDED by @dougiesquire: MOM6 has been updated (MOM6 2026.01.000).
Nice to have icemerg melt spreading but not essential - Anton to let Kieran know PR for this is ready
WW3 - ERA5 work is progressing well