Multiple gem5 instances, make it easier on gem5-shell

README.adoc

@@ -1913,6 +1913,25 @@ Pass options to the `gem5` executable itself:
 ./run -G '-h' -g
 ....
 
+===== Run multiple GEM5 instances at once
+
+GEM5 just assigns new ports if some ports are occupied, so we can do:
+
+....
+./run -g
+# Same as ./gem5-shell 0
+./gem5-shell
+....
+
+And a second instance:
+
+....
+./run -g
+./gem5-shell 1
+....
+
+TODO Now we just need to network them up to have some more fun!
+
 ===== QEMU and GEM5 with the same kernel configuration
 
 We would like to be able to run both GEM5 and QEMU with the same kernel build to avoid duplication, but TODO we haven't been able to get that working yet.

gem5-shell

@@ -1,2 +1,4 @@
 #!/usr/bin/env bash
-telnet localhost "${1:-3456}"
+offset="${1:-0}"
+base=3456
+telnet localhost $(("$base" + "$offset"))