erts: Add new module 'counters'

6 files changed, 111 insertions, 0 deletions

diff --git a/erts/preloaded/ebin/counters.beam b/erts/preloaded/ebin/counters.beam
new file mode 100644
index 0000000000..caaa6167e1
--- /dev/null
+++ b/erts/preloaded/ebin/counters.beam
diff --git a/erts/preloaded/ebin/erts_internal.beam b/erts/preloaded/ebin/erts_internal.beam
index 1ddd367ef5..e174f71966 100644
--- a/erts/preloaded/ebin/erts_internal.beam
+++ b/erts/preloaded/ebin/erts_internal.beam
diff --git a/erts/preloaded/src/Makefile b/erts/preloaded/src/Makefile
index 469086a992..e1bd5bc295 100644
--- a/erts/preloaded/src/Makefile
+++ b/erts/preloaded/src/Makefile
@@ -49,6 +49,7 @@ PRE_LOADED_ERL_MODULES = \
 	erts_literal_area_collector \
 	erts_dirty_process_signal_handler \
 	atomics \
+	counters \
         persistent_term
 
 PRE_LOADED_BEAM_MODULES = \
diff --git a/erts/preloaded/src/counters.erl b/erts/preloaded/src/counters.erl
new file mode 100644
index 0000000000..67354f648d
--- /dev/null
+++ b/erts/preloaded/src/counters.erl
@@ -0,0 +1,90 @@
+%%
+%% %CopyrightBegin%
+%%
+%% Copyright Ericsson AB 2018. All Rights Reserved.
+%%
+%% Licensed under the Apache License, Version 2.0 (the "License");
+%% you may not use this file except in compliance with the License.
+%% You may obtain a copy of the License at
+%%
+%%     http://www.apache.org/licenses/LICENSE-2.0
+%%
+%% Unless required by applicable law or agreed to in writing, software
+%% distributed under the License is distributed on an "AS IS" BASIS,
+%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+%% See the License for the specific language governing permissions and
+%% limitations under the License.
+%%
+%% %CopyrightEnd%
+%%
+
+%% Purpose : Main atomics API module.
+
+-module(counters).
+
+-export([new/2,
+         get/2,
+         add/3,
+         sub/3,
+         info/1]).
+
+-export_type([counters_ref/0]).
+
+-opaque counters_ref() :: {atomics, reference()} | {write_concurrency, reference()}.
+
+-spec new(Size, Opts) -> counters_ref() when
+      Size :: pos_integer(),
+      Opts :: [Opt],
+      Opt :: atomics | write_concurrency.
+new(Size, [atomics]) ->
+    {atomics, atomics:new(Size, [{signed, true}])};
+new(Size, [write_concurrency]) ->
+    {write_concurrency, erts_internal:counters_new(Size)};
+new(Size, []) ->
+    new(Size, [atomics]);
+new(_, _) ->
+    erlang:error(badarg).
+
+-spec get(Ref, Ix) -> integer() when
+      Ref  :: counters_ref(),
+      Ix :: integer().
+get({atomics,Ref}, Ix) ->
+    atomics:get(Ref, Ix);
+get({write_concurrency, Ref}, Ix) ->
+    erts_internal:counters_get(Ref, Ix);
+get(_, _) ->
+    erlang:error(badarg).
+
+
+
+-spec add(Ref, Ix, Incr) -> ok when
+      Ref  :: counters_ref(),
+      Ix :: integer(),
+      Incr :: integer().
+add({atomics, Ref}, Ix, Incr) ->
+    atomics:add(Ref, Ix, Incr);
+add({write_concurrency, Ref}, Ix, Incr) ->
+    erts_internal:counters_add(Ref, Ix, Incr);
+add(_, _, _) ->
+    erlang:error(badarg).
+
+
+-spec sub(Ref, Ix, Decr) -> ok when
+      Ref  :: counters_ref(),
+      Ix :: integer(),
+      Decr :: integer().
+sub(Ref, Ix, Decr) ->
+    add(Ref, Ix, -Decr).
+
+-spec info(Ref) -> Info when
+      Ref  :: counters_ref(),
+      Info :: #{'size':=Size, 'memory':=Memory},
+      Size :: non_neg_integer(),
+      Memory :: non_neg_integer().
+info({atomics, Ref}) ->
+    atomics:info(Ref);
+info({write_concurrency, Ref}) ->
+    erts_internal:counters_info(Ref);
+info(_) ->
+    erlang:error(badarg).
+
diff --git a/erts/preloaded/src/erts.app.src b/erts/preloaded/src/erts.app.src
index c6b82170d3..ed645d1191 100644
--- a/erts/preloaded/src/erts.app.src
+++ b/erts/preloaded/src/erts.app.src
@@ -34,6 +34,7 @@
 		prim_inet,
 		prim_zip,
                 atomics,
+                counters,
 		zlib
 	    ]},
 	{registered, []},
diff --git a/erts/preloaded/src/erts_internal.erl b/erts/preloaded/src/erts_internal.erl
index 64c80a72c3..d491a505c6 100644
--- a/erts/preloaded/src/erts_internal.erl
+++ b/erts/preloaded/src/erts_internal.erl
@@ -94,6 +94,9 @@
 
 -export([atomics_new/2]).
 
+-export([counters_new/1, counters_get/2, counters_add/3,
+         counters_info/1]).
+
 %%
 %% Await result of send to port
 %%
@@ -703,3 +706,19 @@ erase_persistent_terms() ->
 -spec atomics_new(pos_integer(), pos_integer()) -> reference().
 atomics_new(_Arity, _EncOpts) ->
     erlang:nif_error(undef).
+
+-spec counters_new(pos_integer()) -> reference().
+counters_new(_Size) ->
+    erlang:nif_error(undef).
+
+-spec counters_get(reference(), pos_integer()) -> integer().
+counters_get(_Ref, _Ix) ->
+    erlang:nif_error(undef).
+
+-spec counters_add(reference(), pos_integer(), integer()) -> ok.
+counters_add(_Ref, _Ix, _Incr) ->
+    erlang:nif_error(undef).
+
+-spec counters_info(reference()) -> #{}.
+counters_info(_Ref) ->
+    erlang:nif_error(undef).