Investigate timing changes using YOG vs ZM

[jatkinson1000]

CAM output timing files.
Work out what we need to sum/difference to get a meaningful comparison.

[jatkinson1000]

Exploting this with @MarionBWeinzierl there is timing information placed in $CASEROOT under timing/.

The single column cases are really to small to say anything conclusive, so an aquaplanet comparison would be preferable here.

We will also need to extend the level logging operates to to capture the timing that has been implemented for timing yog_nn in physpkg.F90.

[MarionBWeinzierl]

Timing code should be in perf_mod

[jatkinson1000]

perf_mod and timing systems is not part of CAM, but instead part of CIME.
It can be found at cime/src/share/timing/.

CIME timing documentation can be found here: https://esmci.github.io/cime/versions/maint-5.6/html/users_guide/timers.html?highlight=timing

[MarionBWeinzierl]

To be more precise, on Derecho the timing output can be found under /glade/u/<username>/<case>/run/timing. Timing should be on by default, but can be explicitly set by ./xmlchange CHECK_TIMING=TRUE