remote-builds: Specify max jobs

Should make better use of the hardware. Otherwise it's roundtrip frenzy.

os/remote-builds/default.nix

@@ -12,10 +12,12 @@ let
       hostName = "abavorana.frogeye.fr";
       publicHostKey = "c3NoLWVkMjU1MTkgQUFBQUMzTnphQzFsWkRJMU5URTVBQUFBSU5iNzcrS01tRHI0MVhZdmZITXQvK3NHMkJCSEIzYUl4M045WDNVejhFaUogZ2VvZmZyZXlAY3VyYWNhbwo=";
       supportedFeatures = [ "nixos-test" "benchmark" "big-parallel" "kvm" ];
+      maxJobs = 8;
     }
     {
       hostName = "ludwig.clowncar.frogeye.fr";
       publicHostKey = "c3NoLWVkMjU1MTkgQUFBQUMzTnphQzFsWkRJMU5URTVBQUFBSU41SXZhMzNXeGplN095cHVEUHBSakFNMTlvRUtEVDRiYlpUTm82V1FLZTAgZ2VvZmZyZXlAY3VyYWNhbwo=";
+      maxJobs = 4;
     }
   ];
   # MANU pass vivarium/lemmy/remote-builds/cache | nix key convert-secret-to-public | cat
@@ -33,6 +35,9 @@ in
         cat ${pkgs.writeText "root-ssh-config" (lib.strings.concatLines (builtins.map (builder: ''
         Host ${builder.hostName}
           Port 2278
+          ControlMaster auto
+          ControlPath ~/.ssh/master-%r@%n:%p
+          ControlPersist 60s
         '') vivariumBuilders)) } > /root/.ssh/config
       '';
     };