diff options
| -rw-r--r-- | erts/emulator/test/process_SUITE.erl | 50 |
1 files changed, 31 insertions, 19 deletions
diff --git a/erts/emulator/test/process_SUITE.erl b/erts/emulator/test/process_SUITE.erl index e14185e881..a65c3f0cad 100644 --- a/erts/emulator/test/process_SUITE.erl +++ b/erts/emulator/test/process_SUITE.erl @@ -1024,36 +1024,48 @@ bump_big(Prev, Limit) -> %% Priority 'low' should be mixed with 'normal' using a factor of %% about 8. (OTP-2644) low_prio(Config) when is_list(Config) -> - case erlang:system_info(schedulers_online) of - 1 -> - ok = low_prio_test(Config); - _ -> - erlang:system_flag(multi_scheduling, block_normal), - ok = low_prio_test(Config), - erlang:system_flag(multi_scheduling, unblock_normal), - {comment, - "Test not written for SMP runtime system. " - "Multi scheduling blocked during test."} - end. + erlang:system_flag(multi_scheduling, block_normal), + Prop = low_prio_test(Config), + erlang:system_flag(multi_scheduling, unblock_normal), + Str = lists:flatten(io_lib:format("Low/high proportion is ~.3f", + [Prop])), + {comment,Str}. low_prio_test(Config) when is_list(Config) -> process_flag(trap_exit, true), - S = spawn_link(?MODULE, prio_server, [0, 0]), + + %% Spawn the server running with high priority. The server must + %% not run at normal priority as that would skew the results for + %% two reasons: + %% + %% 1. There would be one more normal-priority processes than + %% low-priority processes. + %% + %% 2. The receive queue would grow faster than the server process + %% could process it. That would in turn trigger the reduction + %% punishment for the clients. + S = spawn_opt(?MODULE, prio_server, [0, 0], [link,{priority,high}]), + + %% Spawn the clients and let them run for a while. PCs = spawn_prio_clients(S, erlang:system_info(schedulers_online)), - ct:sleep({seconds,3}), + ct:sleep({seconds,2}), lists:foreach(fun (P) -> exit(P, kill) end, PCs), + + %% Stop the server and retrieve the result. S ! exit, - receive {'EXIT', S, {A, B}} -> check_prio(A, B) end, - ok. + receive + {'EXIT', S, {A, B}} -> + check_prio(A, B) + end. check_prio(A, B) -> Prop = A/B, ok = io:format("Low=~p, High=~p, Prop=~p\n", [A, B, Prop]), - %% It isn't 1/8, it's more like 0.3, but let's check that - %% the low-prio processes get some little chance to run at all. - true = (Prop < 1.0), - true = (Prop > 1/32). + %% Prop is expected to be appr. 1/8. Allow a reasonable margin. + true = Prop < 1/4, + true = Prop > 1/16, + Prop. prio_server(A, B) -> receive |