Allow to enable atop

It may be required to troubleshoot performance related bugs during
tests exection, to have ability to inspect environment processes
and theirs status during test run this patch installs atop
by default if not explicitly disabled.

Related-Bug: #2095224

Change-Id: Iedbd61f3ce3cd2255ea5f2a7a93ba2f39ad28ff2
diff --git a/stack.sh b/stack.sh
index bfa0573..c2a4b5d 100755
--- a/stack.sh
+++ b/stack.sh
@@ -641,6 +641,7 @@
 source $TOP_DIR/lib/neutron
 source $TOP_DIR/lib/ldap
 source $TOP_DIR/lib/dstat
+source $TOP_DIR/lib/atop
 source $TOP_DIR/lib/tcpdump
 source $TOP_DIR/lib/etcd3
 source $TOP_DIR/lib/os-vif
@@ -1093,6 +1094,12 @@
 # A better kind of sysstat, with the top process per time slice
 start_dstat
 
+if is_service_enabled atop; then
+    configure_atop
+    install_atop
+    start_atop
+fi
+
 # Run a background tcpdump for debugging
 # Note: must set TCPDUMP_ARGS with the enabled service
 if is_service_enabled tcpdump; then