Added XNACK support (#94)

* Added xnack flags
* Updated examples compile command

examples/rocshmem_getmem_test.cc

@@ -23,18 +23,36 @@
  *****************************************************************************/
 
 /*
-hipcc -c -fgpu-rdc -x hip rocshmem_getmem_test.cc \
-  -I/opt/rocm/include \
-  -I$ROCSHMEM_INSTALL_DIR/include \
-  -I$OPENMPI_UCX_INSTALL_DIR/include/
+ * First find your offload target, and if xnack is enabled/disabled using
 
-hipcc -fgpu-rdc --hip-link rocshmem_getmem_test.o -o rocshmem_getmem_test \
-  $ROCSHMEM_INSTALL_DIR/lib/librocshmem.a \
-  $OPENMPI_UCX_INSTALL_DIR/lib/libmpi.so \
-  -L/opt/rocm/lib -lamdhip64 -lhsa-runtime64
+   rocminfo | grep amdgcn
 
-ROCSHMEM_MAX_NUM_CONTEXTS=2 mpirun -np 2 ./rocshmem_getmem_test
-*/
+ * It should output a string like so:
+
+   "Name:                    amdgcn-amd-amdhsa--gfx942:sramecc+:xnack-"
+
+ * This lists the offload taret (gfx942) and that xnack is disabled (xnack-).
+ * Therefore, we need to specify --offload-arch=gfx942:xnack- to our link and compile commands.
+ * Please modify the compile and link commands to suit your system
+
+ * To compile:
+   hipcc -c -fgpu-rdc -x hip rocshmem_getmem_test.cc \
+         --offload-arch=<target>:<xnack>             \
+         -I/opt/rocm/include                         \
+         -I$ROCSHMEM_INSTALL_DIR/include             \
+         -I$OPENMPI_UCX_INSTALL_DIR/include/
+
+ * To link:
+   hipcc -fgpu-rdc --hip-link rocshmem_getmem_test.o -o rocshmem_getmem_test \
+         --offload-arch=<target>:<xnack>                                     \
+         $ROCSHMEM_INSTALL_DIR/lib/librocshmem.a                             \
+         $OPENMPI_UCX_INSTALL_DIR/lib/libmpi.so                              \
+         -L/opt/rocm/lib -lamdhip64 -lhsa-runtime64
+
+ * To run:
+   mpirun -np 8 -x ROCSHMEM_MAX_NUM_CONTEXTS=2 ./rocshmem_getmem_test
+
+ */
 
 #include <iostream>