Merge pull request #163 from basho/bugfix/vm-args-scl-false-20

Add +scl and +sub support

Reviewed-by: seancribbs

priv/erlang_vm.schema

@@ -218,8 +218,38 @@
 %% More information: http://www.erlang.org/doc/man/erl.html#+sfwi
 {mapping, "erlang.schedulers.force_wakeup_interval", "vm_args.+sfwi", [
   {commented, 500},
-  {datatype, integer},
-  hidden
+  {datatype, integer}
+]}.
+
+%% @doc Enable or disable scheduler compaction of load. By default
+%% scheduler compaction of load is enabled. When enabled, load
+%% balancing will strive for a load distribution which causes as many
+%% scheduler threads as possible to be fully loaded (i.e., not run out
+%% of work). This is accomplished by migrating load (e.g. runnable
+%% processes) into a smaller set of schedulers when schedulers
+%% frequently run out of work. When disabled, the frequency with which
+%% schedulers run out of work will not be taken into account by the
+%% load balancing logic.
+%%
+%% More information: http://www.erlang.org/doc/man/erl.html#+scl
+{mapping, "erlang.schedulers.compaction_of_load", "vm_args.+scl", [
+  {commented, "false"},
+  {datatype, {enum, [true, false]}}
+]}.
+
+%% @doc Enable or disable scheduler utilization balancing of load. By
+%% default scheduler utilization balancing is disabled and instead
+%% scheduler compaction of load is enabled which will strive for a
+%% load distribution which causes as many scheduler threads as
+%% possible to be fully loaded (i.e., not run out of work). When
+%% scheduler utilization balancing is enabled the system will instead
+%% try to balance scheduler utilization between schedulers. That is,
+%% strive for equal scheduler utilization on all schedulers.
+%%
+%% More information: http://www.erlang.org/doc/man/erl.html#+sub
+{mapping, "erlang.schedulers.utilization_balancing", "vm_args.+sub", [
+  {commented, "true"},
+  {datatype, {enum, [true, false]}}
 ]}.
 
 %% @doc For ease of firewall configuration, the Erlang distribution

test/erlang_vm_schema_tests.erl

@@ -23,6 +23,8 @@ basic_schema_test() ->
     cuttlefish_unit:assert_config(Config, "vm_args.+P", 256000),
     cuttlefish_unit:assert_not_configured(Config, "vm_args.+zdbbl"),
     cuttlefish_unit:assert_not_configured(Config, "vm_args.+sfwi"),
+    cuttlefish_unit:assert_not_configured(Config, "vm_args.+scl"),
+    cuttlefish_unit:assert_not_configured(Config, "vm_args.+sub"),
     cuttlefish_unit:assert_not_configured(Config, "vm_args.-kernel net_ticktime"),
     cuttlefish_unit:assert_not_configured(Config, "kernel.inet_dist_listen_min"),
     cuttlefish_unit:assert_not_configured(Config, "kernel.inet_dist_listen_max"),
@@ -55,6 +57,8 @@ override_schema_test() ->
         {["erlang", "process_limit"], 128001},
         {["erlang", "distribution_buffer_size"], 1024},
         {["erlang", "schedulers", "force_wakeup_interval"], 500},
+        {["erlang", "schedulers", "compaction_of_load"], true},
+        {["erlang", "schedulers", "utilization_balancing"], false},
         {["erlang", "distribution", "port_range", "minimum"], 6000},
         {["erlang", "distribution", "port_range", "maximum"], 7999},
         {["erlang", "distribution", "net_ticktime"], 43}
@@ -75,6 +79,8 @@ override_schema_test() ->
     cuttlefish_unit:assert_config(Config, "vm_args.+P", 128001),
     cuttlefish_unit:assert_config(Config, "vm_args.+zdbbl", 1),
     cuttlefish_unit:assert_config(Config, "vm_args.+sfwi", 500),
+    cuttlefish_unit:assert_config(Config, "vm_args.+scl", true),
+    cuttlefish_unit:assert_config(Config, "vm_args.+sub", false),
     cuttlefish_unit:assert_config(Config, "kernel.inet_dist_listen_min", 6000),
     cuttlefish_unit:assert_config(Config, "kernel.inet_dist_listen_max", 7999),
     cuttlefish_unit:assert_config(Config, "vm_args.-kernel net_ticktime", 43),

test/riak.schema

@@ -1195,8 +1195,20 @@ end}.
 
 %% @doc Erlang VM scheduler tuning.
 %% Prerequisite: a patched VM from Basho, or a VM compiled separately
-%% with this patch applied:
+%% with this patch applied (R15B only):
 %%     https://gist.github.com/evanmcc/a599f4c6374338ed672e
 {mapping, "erlang.swiffy", "vm_args.+sfwi", [
   {commented, "500"}
 ]}.
+
+{mapping, "erlang.scl", "vm_args.+scl", [
+  {commented, "false"},
+  {datatype, {enum, [true, false]}},
+  {level, advanced}
+]}.
+
+{mapping, "erlang.sub", "vm_args.+sub", [
+  {commented, "true"},
+  {datatype, {enum, [true, false]}},
+  {level, advanced}
+]}.