cam6_4_131: Performance improvements for CSLAM (from John Dennis, CISL, and Lauritzen)

doc/ChangeLog

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+
+Tag name: cam6_
+Originator(s): johnmauff, pel
+Date: April 28, 2025
+One-line Summary:
+Github PR URL: https://github.com/ESCOMP/CAM/pull/
+
+Purpose of changes (include the issue number and title text for each relevant GitHub issue):
+   Excessive data movement in extend_panel_interpolate (CSLAM): https://github.com/ESCOMP/CAM/issues/1316
+
+   The subroutine extend_panel_interpolate is written such that the compiler will generate more data movement than is necessary.
+   This excessive data movement intensifies a computational load imbalance in the CSLAM advection. While it is impossible to eliminate
+   the load imbalance that is caused by the special treatment of panels at the corners of the cubed sphere, it is possible to reduce
+   the cost of this subroutine by changing the way that the subroutine is written.
+
+Describe any changes made to build system: N/A
+
+Describe any changes made to the namelist: N/A
+
+List any changes to the defaults for the boundary datasets: N/A
+
+Describe any substantial timing or memory changes: N/A
+
+Code reviewed by:
+
+List all files eliminated: N/A
+
+List all files added and what they do: N/A
+
+List all existing files that have been modified, and describe the changes:
+
+....
+
+Summarize any changes to answers:
+	No answer changes, all b4b
 
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