erts: Add new module 'counters'

16 files changed, 596 insertions, 1 deletions

diff --git a/erts/doc/src/Makefile b/erts/doc/src/Makefile
index 56f8f40069..40f74b78ff 100644
--- a/erts/doc/src/Makefile
+++ b/erts/doc/src/Makefile
@@ -54,6 +54,7 @@ XML_REF3_EFILES = \
 	init.xml \
 	persistent_term.xml \
 	atomics.xml \
+	counters.xml \
 	zlib.xml
 
 XML_REF3_FILES = \
diff --git a/erts/doc/src/counters.xml b/erts/doc/src/counters.xml
new file mode 100644
index 0000000000..85eedfdadc
--- /dev/null
+++ b/erts/doc/src/counters.xml
@@ -0,0 +1,142 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<!DOCTYPE erlref SYSTEM "erlref.dtd">
+
+<erlref>
+  <header>
+    <copyright>
+      <year>2018</year>
+      <holder>Ericsson AB. All Rights Reserved.</holder>
+    </copyright>
+    <legalnotice>
+      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.
+    </legalnotice>
+
+    <title>counters</title>
+  </header>
+  <module>counters</module>
+  <modulesummary>Counter Functions</modulesummary>
+  <description>
+    <p>This module provides a set of functions to do operations towards
+    shared mutable counter variables. The implementation does not utilize any
+    software level locking, which makes it very efficient for concurrent
+    access. The counters are organized into arrays with the follwing
+    semantics:</p>
+    <list type="bulleted">
+      <item>
+	<p>Counters are 64 bit signed integers.</p>
+      </item>
+      <item>
+	<p>Counters wrap around at overflow and underflow operations.</p>
+      </item>
+      <item><p>Counters are initialized to zero and can then only be written to
+        by adding or subtracting.</p>
+      </item>
+      <item>
+	<p>Write operations guarantee atomicity. No intermediate results can be
+	seen from a single write operation.</p>
+      </item>
+      <item>
+	<p>Two types of counter arrays can be created with options <c>atomics</c> or
+	<c>write_concurrency</c>. The <c>atomics</c> counters have good allround
+	performance with nice consistent semantics while
+	<c>write_concurrency</c> counters offers even better concurrent
+	write performance at the expense of some potential read
+	inconsistencies. See <seealso marker="#new/2"><c>new/2</c></seealso>.</p>
+      </item>
+      <item>
+	<p>Indexes into counter arrays are one-based. A counter array of
+	size N contains N counters with index from 1 to N.</p>
+      </item>
+    </list>
+  </description>
+
+  <datatypes>
+    <datatype>
+      <name name="counters_ref"/>
+      <desc><p>Identifies a counter array returned from
+        <seealso marker="#new/2"><c>new/2</c></seealso>.</p>
+      </desc>
+    </datatype>
+  </datatypes>
+
+  <funcs>
+    <func>
+      <name name="new" arity="2"/>
+      <fsummary>Create counter array</fsummary>
+      <desc>
+        <p>Create a new counter array of <c><anno>Size</anno></c> counters.</p>
+	<p>Argument <c><anno>Opts</anno></c> is a list of the following possible
+	options:</p>
+	<taglist>
+	  <tag><c>atomics</c> (Default)</tag>
+	  <item><p>Counters will be sequentially consistent. If write
+	  operation A is done sequencially before write operation B, then a concurrent reader
+	  may see none of them, only A, or both A and B. It cannot see only B.</p>
+	  </item>
+	  <tag><c>write_concurrency</c></tag>
+	  <item><p>This is an optimization to achieve very efficient concurrent
+	  write operations at the expense of potential read inconsistency and memory
+	  consumption per counter.</p>
+	  <p>Read operations may see sequentially inconsistent results with
+	  regard to concurrent write operations. Even if write operation A is done
+	  sequencially before write operation B, a concurrent reader may see any
+	  combination of A and B, including only B. A read operation is only
+	  guaranteed to see all writes done sequentially before the read. No writes
+	  are ever lost, but will eventually all be seen.</p>
+	  </item>
+	</taglist>
+      </desc>
+    </func>
+
+    <func>
+      <name name="get" arity="2"/>
+      <fsummary>Read counter value</fsummary>
+      <desc>
+        <p>Read counter value.</p>
+      </desc>
+    </func>
+
+    <func>
+      <name name="add" arity="3"/>
+      <fsummary>Add to counter</fsummary>
+      <desc>
+        <p>Add <c><anno>Incr</anno></c> to counter.</p>
+      </desc>
+    </func>
+
+    <func>
+      <name name="sub" arity="3"/>
+      <fsummary>Subtract from counter</fsummary>
+      <desc>
+        <p>Subtract <c><anno>Decr</anno></c> from counter.</p>
+      </desc>
+    </func>
+
+    <func>
+      <name name="info" arity="1"/>
+      <fsummary>Get information about counter array.</fsummary>
+      <desc>
+        <p>Return information about a counter array in a map. The map
+	has the following keys (at least):</p>
+	<taglist>
+	  <tag><c>size</c></tag>
+	  <item><p>The number of counters in the array.</p></item>
+	  <tag><c>memory</c></tag>
+	  <item><p>Approximate memory consumption for the array in
+	  bytes.</p></item>
+	</taglist>
+      </desc>
+    </func>
+
+ </funcs>
+</erlref>
diff --git a/erts/doc/src/ref_man.xml b/erts/doc/src/ref_man.xml
index 98f7bbbb8b..a78aaa449e 100644
--- a/erts/doc/src/ref_man.xml
+++ b/erts/doc/src/ref_man.xml
@@ -51,5 +51,6 @@
   <xi:include href="erl_nif.xml"/>
   <xi:include href="erl_tracer.xml"/>
   <xi:include href="atomics.xml"/>
+  <xi:include href="counters.xml"/>
 </application>
 
diff --git a/erts/doc/src/specs.xml b/erts/doc/src/specs.xml
index 784212dfa0..0b943e6295 100644
--- a/erts/doc/src/specs.xml
+++ b/erts/doc/src/specs.xml
@@ -7,4 +7,5 @@
   <xi:include href="../specs/specs_persistent_term.xml"/>
   <xi:include href="../specs/specs_zlib.xml"/>
   <xi:include href="../specs/specs_atomics.xml"/>
+  <xi:include href="../specs/specs_counters.xml"/>
 </specs>
diff --git a/erts/emulator/Makefile.in b/erts/emulator/Makefile.in
index 7fa29a7f2e..57a9d45887 100644
--- a/erts/emulator/Makefile.in
+++ b/erts/emulator/Makefile.in
@@ -649,6 +649,7 @@ PRELOAD_BEAM =	$(ERL_TOP)/erts/preloaded/ebin/otp_ring0.beam \
 		$(ERL_TOP)/erts/preloaded/ebin/erts_literal_area_collector.beam \
 		$(ERL_TOP)/erts/preloaded/ebin/erts_dirty_process_signal_handler.beam \
 		$(ERL_TOP)/erts/preloaded/ebin/atomics.beam \
+		$(ERL_TOP)/erts/preloaded/ebin/counters.beam \
 		$(ERL_TOP)/erts/preloaded/ebin/persistent_term.beam
 
 ifeq ($(TARGET),win32)
@@ -842,7 +843,7 @@ RUN_OBJS += \
 	$(OBJDIR)/erl_bif_info.o	$(OBJDIR)/erl_bif_op.o \
 	$(OBJDIR)/erl_bif_os.o		$(OBJDIR)/erl_bif_lists.o \
 	$(OBJDIR)/erl_bif_persistent.o \
-	$(OBJDIR)/erl_bif_atomics.o \
+	$(OBJDIR)/erl_bif_atomics.o    	$(OBJDIR)/erl_bif_counters.o \
 	$(OBJDIR)/erl_bif_trace.o	$(OBJDIR)/erl_bif_unique.o \
 	$(OBJDIR)/erl_bif_wrap.o	$(OBJDIR)/erl_nfunc_sched.o \
 	$(OBJDIR)/erl_guard_bifs.o 	$(OBJDIR)/erl_dirty_bif_wrap.o \
diff --git a/erts/emulator/beam/bif.tab b/erts/emulator/beam/bif.tab
index 0577c5722f..aa3c3acd9f 100644
--- a/erts/emulator/beam/bif.tab
+++ b/erts/emulator/beam/bif.tab
@@ -719,3 +719,8 @@ bif atomics:add_get/3
 bif atomics:exchange/3
 bif atomics:compare_exchange/4
 bif atomics:info/1
+
+bif erts_internal:counters_new/1
+bif erts_internal:counters_get/2
+bif erts_internal:counters_add/3
+bif erts_internal:counters_info/1
diff --git a/erts/emulator/beam/erl_alloc.types b/erts/emulator/beam/erl_alloc.types
index aefa04a031..4f03a34390 100644
--- a/erts/emulator/beam/erl_alloc.types
+++ b/erts/emulator/beam/erl_alloc.types
@@ -339,6 +339,7 @@ type	PORT_DATA_HEAP	STANDARD	SYSTEM		port_data_heap
 type    MSACC           DRIVER          SYSTEM          microstate_accounting
 type	SYS_CHECK_REQ	SHORT_LIVED	SYSTEM		system_check_request
 type	ATOMICS		STANDARD	SYSTEM		erl_bif_atomics
+type	COUNTERS	STANDARD	SYSTEM		erl_bif_counters
 
 #
 # Types used by system specific code
diff --git a/erts/emulator/beam/erl_bif_counters.c b/erts/emulator/beam/erl_bif_counters.c
new file mode 100644
index 0000000000..a46b462225
--- /dev/null
+++ b/erts/emulator/beam/erl_bif_counters.c
@@ -0,0 +1,219 @@
+/*
+ * %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:  High performance atomics.
+ */
+
+#ifdef HAVE_CONFIG_H
+#  include "config.h"
+#endif
+
+#include <stddef.h> /* offsetof */
+
+#include "sys.h"
+#include "export.h"
+#include "bif.h"
+#include "erl_threads.h"
+#include "big.h"
+#include "erl_binary.h"
+#include "erl_bif_unique.h"
+#include "erl_map.h"
+
+
+#define COUNTERS_PER_CACHE_LINE (ERTS_CACHE_LINE_SIZE / sizeof(erts_atomic64_t))
+
+typedef struct
+{
+    UWord arity;
+#ifdef DEBUG
+    UWord ulen;
+#endif
+    union {
+        erts_atomic64_t v[COUNTERS_PER_CACHE_LINE];
+        byte cache_line__[ERTS_CACHE_LINE_SIZE];
+    } u[1];
+}CountersRef;
+
+static int counters_destructor(Binary *unused)
+{
+    return 1;
+}
+
+
+static UWord ERTS_INLINE div_ceil(UWord dividend, UWord divisor)
+{
+    return (dividend + divisor - 1) / divisor;
+}
+
+BIF_RETTYPE erts_internal_counters_new_1(BIF_ALIST_1)
+{
+    CountersRef* p;
+    Binary* mbin;
+    UWord ui, vi, cnt;
+    Uint bytes, cache_lines;
+    Eterm* hp;
+
+    if (!term_to_UWord(BIF_ARG_1, &cnt)
+        || cnt == 0) {
+        BIF_ERROR(BIF_P, BADARG);
+    }
+
+    if (cnt > (ERTS_UWORD_MAX / (sizeof(erts_atomic64_t)*2*erts_no_schedulers)))
+        BIF_ERROR(BIF_P, SYSTEM_LIMIT);
+
+    cache_lines = erts_no_schedulers * div_ceil(cnt, COUNTERS_PER_CACHE_LINE);
+    bytes = offsetof(CountersRef, u) + cache_lines * ERTS_CACHE_LINE_SIZE;
+    mbin = erts_create_magic_binary_x(bytes,
+                                      counters_destructor,
+                                      ERTS_ALC_T_ATOMICS,
+                                      0);
+    p = ERTS_MAGIC_BIN_DATA(mbin);
+    p->arity = cnt;
+#ifdef DEBUG
+    p->ulen = cache_lines;
+#endif
+    ASSERT((byte*)&p->u[cache_lines] <= ((byte*)p + bytes));
+    for (ui=0; ui < cache_lines; ui++)
+        for (vi=0; vi < COUNTERS_PER_CACHE_LINE; vi++)
+            erts_atomic64_init_nob(&p->u[ui].v[vi], 0);
+    hp = HAlloc(BIF_P, ERTS_MAGIC_REF_THING_SIZE);
+    return erts_mk_magic_ref(&hp, &MSO(BIF_P), mbin);
+}
+
+static ERTS_INLINE int get_ref(Eterm ref, CountersRef** pp)
+{
+    Binary* mbin;
+    if (!is_internal_magic_ref(ref))
+        return 0;
+
+    mbin = erts_magic_ref2bin(ref);
+    if (ERTS_MAGIC_BIN_DESTRUCTOR(mbin) != counters_destructor)
+        return 0;
+    *pp = ERTS_MAGIC_BIN_DATA(mbin);
+    return 1;
+}
+
+static ERTS_INLINE int get_ref_cnt(Eterm ref, Eterm index,
+                                   CountersRef** pp,
+                                   erts_atomic64_t** app,
+                                   UWord sched_ix)
+{
+    CountersRef* p;
+    UWord ix, ui, vi;
+    if (!get_ref(ref, &p) || !term_to_UWord(index, &ix) || --ix >= p->arity)
+        return 0;
+    ui = (ix / COUNTERS_PER_CACHE_LINE) * erts_no_schedulers + sched_ix;
+    vi = ix % COUNTERS_PER_CACHE_LINE;
+    ASSERT(ui < p->ulen);
+    *pp = p;
+    *app = &p->u[ui].v[vi];
+    return 1;
+}
+
+static ERTS_INLINE int get_ref_my_cnt(Eterm ref, Eterm index,
+                                      CountersRef** pp,
+                                      erts_atomic64_t** app)
+{
+    ErtsSchedulerData *esdp = erts_get_scheduler_data();
+    ASSERT(esdp && !ERTS_SCHEDULER_IS_DIRTY(esdp));
+    return get_ref_cnt(ref, index, pp, app, esdp->no - 1);
+}
+
+static ERTS_INLINE int get_ref_first_cnt(Eterm ref, Eterm index,
+                                         CountersRef** pp,
+                                         erts_atomic64_t** app)
+{
+    return get_ref_cnt(ref, index, pp, app, 0);
+}
+
+static ERTS_INLINE int get_incr(CountersRef* p, Eterm term, erts_aint64_t *valp)
+{
+    return (term_to_Sint64(term, (Sint64*)valp)
+            || term_to_Uint64(term, (Uint64*)valp));
+}
+
+static ERTS_INLINE Eterm bld_counter(Process* proc, CountersRef* p,
+                                     erts_aint64_t val)
+{
+    if (IS_SSMALL(val))
+        return make_small((Sint) val);
+    else {
+        Uint hsz = ERTS_SINT64_HEAP_SIZE(val);
+        Eterm* hp = HAlloc(proc, hsz);
+        return erts_sint64_to_big(val, &hp);
+    }
+}
+
+BIF_RETTYPE erts_internal_counters_get_2(BIF_ALIST_2)
+{
+    CountersRef* p;
+    erts_atomic64_t* ap;
+    erts_aint64_t acc = 0;
+    int j;
+
+    if (!get_ref_first_cnt(BIF_ARG_1, BIF_ARG_2, &p, &ap)) {
+        BIF_ERROR(BIF_P, BADARG);
+    }
+    for (j = erts_no_schedulers; j ; --j) {
+        acc += erts_atomic64_read_nob(ap);
+        ap = (erts_atomic64_t*) ((byte*)ap + ERTS_CACHE_LINE_SIZE);
+    }
+    return bld_counter(BIF_P, p, acc);
+}
+
+BIF_RETTYPE erts_internal_counters_add_3(BIF_ALIST_3)
+{
+    CountersRef* p;
+    erts_atomic64_t* ap;
+    erts_aint64_t incr, sum;
+
+    if (!get_ref_my_cnt(BIF_ARG_1, BIF_ARG_2, &p, &ap)
+        || !get_incr(p, BIF_ARG_3, &incr)) {
+        BIF_ERROR(BIF_P, BADARG);
+    }
+    sum = incr + erts_atomic64_read_nob(ap);
+    erts_atomic64_set_nob(ap, sum);
+    return am_ok;
+}
+
+
+BIF_RETTYPE erts_internal_counters_info_1(BIF_ALIST_1)
+{
+    CountersRef* p;
+    Uint hsz = MAP2_SZ;
+    Eterm *hp;
+    UWord memory;
+    Eterm sz_val, mem_val;
+
+    if (!get_ref(BIF_ARG_1, &p))
+        BIF_ERROR(BIF_P, BADARG);
+
+    memory = erts_magic_ref2bin(BIF_ARG_1)->orig_size;
+    erts_bld_uword(NULL, &hsz, p->arity);
+    erts_bld_uword(NULL, &hsz, memory);
+
+    hp = HAlloc(BIF_P, hsz);
+    sz_val  = erts_bld_uword(&hp, NULL, p->arity);
+    mem_val = erts_bld_uword(&hp, NULL, memory);
+
+    return MAP2(hp, am_memory, mem_val,
+                am_size, sz_val);
+}
diff --git a/erts/emulator/test/Makefile b/erts/emulator/test/Makefile
index fc395899b8..6a064ec8d4 100644
--- a/erts/emulator/test/Makefile
+++ b/erts/emulator/test/Makefile
@@ -51,6 +51,7 @@ MODULES= \
 	call_trace_SUITE \
 	code_SUITE \
 	code_parallel_load_SUITE \
+	counters_SUITE \
 	crypto_SUITE \
 	ddll_SUITE \
 	decode_packet_SUITE \
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.
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).