erts: Add new module 'counters'

1 files changed, 112 insertions, 0 deletions

diff --git a/erts/emulator/test/counters_SUITE.erl b/erts/emulator/test/counters_SUITE.erl
new file mode 100644
index 0000000000..7de164096b
--- /dev/null
+++ b/erts/emulator/test/counters_SUITE.erl
@@ -0,0 +1,112 @@
+%%
+%% %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%
+%%
+-module(counters_SUITE).
+
+-include_lib("common_test/include/ct.hrl").
+
+-compile(export_all).
+
+suite() -> [{ct_hooks,[ts_install_cth]}].
+
+all() ->
+    [basic, bad, limits].
+
+basic(Config) when is_list(Config) ->
+    Size = 10,
+    [begin
+         Ref = counters:new(Size,[Type]),
+         #{size:=Size, memory:=Memory} = counters:info(Ref),
+         check_memory(Type, Memory, Size),
+         [basic_do(Ref, Ix) || Ix <- lists:seq(1, Size)]
+     end
+     || Type <- [atomics, write_concurrency]],
+    ok.
+
+basic_do(Ref, Ix) ->
+    0 = counters:get(Ref, Ix),
+    ok = counters:add(Ref, Ix, 3),
+    3  = counters:get(Ref, Ix),
+    ok = counters:add(Ref, Ix, 14),
+    17  = counters:get(Ref, Ix),
+    ok = counters:add(Ref, Ix, -20),
+    -3  = counters:get(Ref, Ix),
+    ok = counters:add(Ref, Ix, 100),
+    97 = counters:get(Ref, Ix),
+    ok = counters:sub(Ref, Ix, 20),
+    77 = counters:get(Ref, Ix),
+    ok = counters:sub(Ref, Ix, -10),
+    87 = counters:get(Ref, Ix),
+    ok.
+
+check_memory(atomics, Memory, Size) ->
+    {_,true} = {Memory, Memory > Size*8},
+    {_,true} = {Memory, Memory < Size*max_atomic_sz() + 100};
+check_memory(write_concurrency, Memory, Size) ->
+    NScheds = erlang:system_info(schedulers),
+    {_,true} = {Memory, Memory > NScheds*Size*8},
+    {_,true} = {Memory, Memory < NScheds*(Size+7)*max_atomic_sz() + 100}.
+
+max_atomic_sz() ->
+    case erlang:system_info({wordsize, external}) of
+        4 -> 16;
+        8 ->
+            EI = erlang:system_info(ethread_info),
+            case lists:keyfind("64-bit native atomics", 1, EI) of
+                {_, "no", _} -> 16;
+                _ -> 8
+            end
+    end.
+
+bad(Config) when is_list(Config) ->
+    {'EXIT',{badarg,_}} = (catch counters:new(0,[])),
+    {'EXIT',{badarg,_}} = (catch counters:new(10,[bad])),
+    {'EXIT',{badarg,_}} = (catch counters:new(10,[atomic, bad])),
+    {'EXIT',{badarg,_}} = (catch counters:new(10,[write_concurrency | bad])),
+    Ref = counters:new(10,[]),
+    {'EXIT',{badarg,_}} = (catch counters:get(1742, 7)),
+    {'EXIT',{badarg,_}} = (catch counters:get(make_ref(), 7)),
+    {'EXIT',{badarg,_}} = (catch counters:get(Ref, -1)),
+    {'EXIT',{badarg,_}} = (catch counters:get(Ref, 0)),
+    {'EXIT',{badarg,_}} = (catch counters:get(Ref, 11)),
+    {'EXIT',{badarg,_}} = (catch counters:get(Ref, 7.0)),
+    ok.
+
+
+limits(Config) when is_list(Config) ->
+    Bits = 64,
+    Max = (1 bsl (Bits-1)) - 1,
+    Min = -(1 bsl (Bits-1)),
+
+    Ref = counters:new(1,[]),
+    0 = counters:get(Ref, 1),
+    ok = counters:add(Ref, 1, Max),
+    ok = counters:add(Ref, 1, 1),
+    Min = counters:get(Ref, 1),
+    ok  = counters:sub(Ref, 1, 1),
+    Max = counters:get(Ref, 1),
+
+    IncrMax = (Max bsl 1) bor 1,
+    ok = counters:sub(Ref, 1, counters:get(Ref, 1)),
+    ok = counters:add(Ref, 1, IncrMax),
+    -1 = counters:get(Ref, 1),
+    {'EXIT',{badarg,_}} = (catch counters:add(Ref, 1, IncrMax+1)),
+    {'EXIT',{badarg,_}} = (catch counters:add(Ref, 1, Min-1)),
+
+    ok.