Optimize PE layouts for Derecho

[samsrabin]

Waiting on #1995, where some initial PE layouts will be implemented.

[ekluzek]

For this we should optimize PE layouts for important grids. Here's my initial cut at that list:

f09
f19
ne30np4.pg3
hcru
nldas2
f45
f10
C96
mpasa120

We might need to optimize for high and ultra-high resolutions grids if that's important for CAM and groups working on these resolutions (if they are going to simulations with standalone CLM).

[ekluzek]

There's also "S" PE layouts for f09 and f19 as well as nldas2 and those should be optimized as well.

We currently also have PE layouts for: f05, f02, ne240, C384, C192, and T31 that we can drop.

And there are specific PE layouts for the following (from grep on the config_pes.xml file). We should check if all of these should be supported as well @adamrher?...)

  <grid name="l%ne0np4CONUS" >
  <grid name="l%ne0np4CONUS" >
  <grid name="l%ne0np4.ARCTICGRIS.ne30" >
  <grid name="l%ne0np4.ARCTICGRIS.ne30" >
  <grid name="l%ne0np4.ARCTIC.ne30" >
  <grid name="l%ne0np4.ARCTIC.ne30" >
  <grid name="l%ne120">

[ekluzek]

In #1967 here #1967 (comment)

I found that the PE layouts for a lot of resolutions just use one node, and if memory increases just a bit, that tests can fail because not enough processors are used. So it would be good to increase the PE layout size for the resolutions I discovered problems with there.

[wwieder]

also closing this issue (for now)