add new xml vars for GPU configuration

Author: sjsprecious

cime_config/config_component.xml

@@ -795,20 +795,38 @@
 
   <entry id="GPU_TYPE">
     <type>char</type>
-    <valid_values></valid_values>
-    <default_value></default_value>
+    <valid_values MACH="derecho">none,a100</valid_values>
+    <default_value>none</default_value>
     <group>build_def</group>
     <file>env_build.xml</file>
     <desc>If set will compile and submit with this gpu type enabled </desc>
   </entry>
 
-  <entry id="GPU_OFFLOAD">
-    <type>char</type>
-    <valid_values></valid_values>
-    <default_value></default_value>
+  <entry id="OPENACC_GPU_OFFLOAD">
+    <type>logical</type>
+    <valid_values>TRUE,FALSE</valid_values>
+    <default_value>FALSE</default_value>
     <group>build_def</group>
     <file>env_build.xml</file>
-    <desc>If set will compile and submit with this gpu offload method enabled </desc>
+    <desc>True=>compile the GPU code with OpenACC GPU flags </desc>
+  </entry>
+
+  <entry id="OPENMP_GPU_OFFLOAD">
+    <type>logical</type>
+    <valid_values>TRUE,FALSE</valid_values>
+    <default_value>FALSE</default_value>
+    <group>build_def</group>
+    <file>env_build.xml</file>
+    <desc>True=>compile the GPU code with OpenMP GPU flags </desc>
+  </entry>
+
+  <entry id="KOKKOS_GPU_OFFLOAD">
+    <type>logical</type>
+    <valid_values>TRUE,FALSE</valid_values>
+    <default_value>FALSE</default_value>
+    <group>build_def</group>
+    <file>env_build.xml</file>
+    <desc>True=>compile the GPU code with KOKKOS GPU target </desc>
   </entry>
 
   <entry id="MPI_GPU_WRAPPER_SCRIPT">
@@ -818,7 +836,7 @@
     <group>build_def</group>
     <file>env_build.xml</file>
     <desc>If set will attach this script to the MPI run command, mapping
-    different MPI ranks to different GPUs within the same compute node</desc>
+    different MPI ranks to different GPUs within the same compute node </desc>
   </entry>
 
   <entry id="ESMF_AWARE_THREADING">
@@ -1774,33 +1792,36 @@
   <entry id="MAX_CPUTASKS_PER_GPU_NODE">
     <type>integer</type>
     <default_value>0</default_value>
-    <values>
-      <value compiler="nvhpc">1</value>
-    </values>
     <group>mach_pes_last</group>
     <file>env_mach_pes.xml</file>
-    <desc> Number of CPU cores per GPU node used for simulation </desc>
+    <desc>Number of CPU cores per GPU node used for simulation </desc>
+  </entry>
+
+  <entry id="OVERSUBSCRIBE_GPU">
+    <type>logical</type>
+    <valid_values>TRUE,FALSE</valid_values>
+    <default_value>FALSE</default_value>
+    <group>mach_pes</group>
+    <file>env_mach_pes.xml</file>
+    <desc>False=>assign only one MPI task per GPU; True=>assign multiple MPI tasks per GPU </desc>
   </entry>
 
   <entry id="NGPUS_PER_NODE">
     <type>integer</type>
     <default_value>0</default_value>
-    <values>
-      <value compiler="nvhpc">1</value>
-    </values>
     <group>mach_pes</group>
     <file>env_mach_pes.xml</file>
-    <desc> Number of GPUs per node used for simulation </desc>
+    <desc>Number of GPUs per node used for simulation </desc>
   </entry>
-
+  
   <entry id="MAX_GPUS_PER_NODE">
     <type>integer</type>
     <default_value>0</default_value>
     <group>mach_pes_last</group>
     <file>env_mach_pes.xml</file>
-    <desc>maximum number of GPUs allowed per node </desc>
+    <desc>Maximum number of GPUs allowed per node </desc>
   </entry>
-
+  
   <entry id="COSTPES_PER_NODE">
     <type>integer</type>
     <default_value>$MAX_MPITASKS_PER_NODE</default_value>