diff options
| -rw-r--r-- | erts/emulator/beam/erl_bif_counters.c | 2 | ||||
| -rw-r--r-- | erts/emulator/test/counters_SUITE.erl | 61 |
2 files changed, 60 insertions, 3 deletions
diff --git a/erts/emulator/beam/erl_bif_counters.c b/erts/emulator/beam/erl_bif_counters.c index 84496e83ef..7c8884ba32 100644 --- a/erts/emulator/beam/erl_bif_counters.c +++ b/erts/emulator/beam/erl_bif_counters.c @@ -130,7 +130,7 @@ static ERTS_INLINE int get_ref_cnt(Eterm ref, Eterm index, UWord ix, ui, vi; if (!get_ref(ref, &p) || !term_to_UWord(index, &ix) || --ix >= p->arity) return 0; - ui = (ix / ATOMICS_PER_CACHE_LINE) * ATOMICS_PER_COUNTER; + ui = (ix / ATOMICS_PER_CACHE_LINE) * ATOMICS_PER_COUNTER + sched_ix; vi = ix % ATOMICS_PER_CACHE_LINE; ASSERT(ui < p->ulen); *pp = p; diff --git a/erts/emulator/test/counters_SUITE.erl b/erts/emulator/test/counters_SUITE.erl index 8cc963e3b9..b3f0358c1e 100644 --- a/erts/emulator/test/counters_SUITE.erl +++ b/erts/emulator/test/counters_SUITE.erl @@ -22,12 +22,12 @@ -include_lib("common_test/include/ct.hrl"). -export([suite/0, all/0]). --export([basic/1, bad/1, limits/1, indep/1]). +-export([basic/1, bad/1, limits/1, indep/1, write_concurrency/1]). suite() -> [{ct_hooks,[ts_install_cth]}]. all() -> - [basic, bad, limits, indep]. + [basic, bad, limits, indep, write_concurrency]. basic(Config) when is_list(Config) -> Size = 10, @@ -175,3 +175,60 @@ indep_subber(Ref, I, Val) when Val > -(1 bsl 62) -> indep_subber(Ref, I, Res); indep_subber(_Ref, _I, Val) -> Val. + + + +%% Verify write_concurrency yields correct results. +write_concurrency(Config) when is_list(Config) -> + rand:seed(exs1024s), + io:format("*** SEED: ~p ***\n", [rand:export_seed()]), + NScheds = erlang:system_info(schedulers), + Size = 100, + Ref = counters:new(Size,[write_concurrency]), + Rounds = 1000, + Papa = self(), + Pids = [spawn_opt(fun Worker() -> + receive + {go, Ix, Incr} -> + wc_looper(Rounds, Ref, Ix, Incr), + Papa ! {self(), done, Rounds*Incr}, + Worker(); + stop -> + ok + end + end, + [link, {scheduler, N}]) + || N <- lists:seq(1, NScheds)], + [begin + Base = rand_log64(), + counters:put(Ref, Index, Base), + SendList = [{P,{go, Index, rand_log64()}} || P <- Pids], + [P ! Msg || {P,Msg} <- SendList], + Added = lists:sum([receive {P,done,Contrib} -> Contrib end || P <- Pids]), + Result = mask_sint64(Base+Added), + {_,Result} = {Result, counters:get(Ref, Index)} + end + || Index <- lists:seq(1, Size)], + + [begin unlink(P), P ! stop end || P <- Pids], + ok. + +wc_looper(0, _, _, _) -> + ok; +wc_looper(N, Ref, Ix, Incr) -> + counters:add(Ref, Ix, Incr), + wc_looper(N-1, Ref, Ix, Incr). + +mask_sint64(X) -> + SMask = 1 bsl 63, + UMask = SMask - 1, + (X band UMask) - (X band SMask). + +%% A random signed 64-bit integer +%% with a uniformly distributed number of significant bits. +rand_log64() -> + Uint = round(math:pow(2, rand:uniform()*63)), + case rand:uniform(2) of + 1 -> -Uint; + 2 -> Uint + end. |