notes on using spack for mochi on cooley

tests/perf-regression/cooley/README.spack.md

+To compile the full stack on cooley as of June 2018 using spack:
+
+# set up .soft.cooley like this:
+```
++gcc-7.1.0
++autotools-feb2016
++cmake-3.9.1
++mvapich2
+@default
+```
+
+# get spack repos:
+```
+git clone https://github.com/spack/spack.git
+. spack/share/spack/setup-env.sh
+spack bootstrap
+git clone git@xgitlab.cels.anl.gov:sds/sds-repo
+spack repo add .
+```
+
+# edit .spack/linux/packages.yaml to look like this:
+```
+packages:
+    openssl:
+        paths:
+            openssl@1.0.2k: /usr
+        buildable: False
+    cmake:
+        paths:
+            cmake@3.9.1: /soft/buildtools/cmake/3.9.1
+        buildable: False
+    autoconf:
+        paths:
+            autoconf@2.69: /soft/buildtools/autotools/feb2016
+        buildable: False
+    automake:
+        paths:
+            automake@1.15: /soft/buildtools/autotools/feb2016
+        buildable: False
+    ssg:
+        variants: +mpi
+    libfabric:
+        variants: fabrics=verbs,rxm
+    all:
+        providers:
+            # prefer MPICH by default
+            mpi: [mpich,openmpi]
+
+```
+
+# compile everything and load module for ssg
+# note that the --dirty option is needed because gcc 7.1 on cooley only works if it can inherit LD_LIBRARY_PATH from softenv
+spack install --dirty ssg
+spack load -r ssg
+
+TODO: at this point ssg tests need to be updated to skip using abt-snoozer
+