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authorPatrik Nyblom <[email protected]>2013-08-16 17:14:25 +0200
committerPatrik Nyblom <[email protected]>2013-08-23 17:03:20 +0200
commit6d1f1d43aa0a9e0a2cb275ef760339c49518fc69 (patch)
treec51d17da4e41d64eddb42a4918a3f9d2b5967ded /erts/emulator/test
parent7204e78d8d16e41769cfd4b7b4051545052c335e (diff)
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Create better distribution of files over async threads
The actual port id is used to create a key from the pointer value which is the ErlDrvPort. To do this a new driver api function driver_async_port_key is added and the driver API minor version is updated. The documentation is updated and the faulty description of how to spread ports over async threads is updated to use the new API. Testcase also added.
Diffstat (limited to 'erts/emulator/test')
-rw-r--r--erts/emulator/test/efile_SUITE.erl88
1 files changed, 83 insertions, 5 deletions
diff --git a/erts/emulator/test/efile_SUITE.erl b/erts/emulator/test/efile_SUITE.erl
index 65367eab98..f79bb761d1 100644
--- a/erts/emulator/test/efile_SUITE.erl
+++ b/erts/emulator/test/efile_SUITE.erl
@@ -19,16 +19,16 @@
-module(efile_SUITE).
-export([all/0, suite/0,groups/0,init_per_suite/1, end_per_suite/1,
init_per_group/2,end_per_group/2]).
--export([iter_max_files/1]).
+-export([iter_max_files/1, async_dist/1]).
--export([do_iter_max_files/2]).
+-export([do_iter_max_files/2, do_async_dist/1]).
-include_lib("test_server/include/test_server.hrl").
suite() -> [{ct_hooks,[ts_install_cth]}].
all() ->
- [iter_max_files].
+ [iter_max_files, async_dist].
groups() ->
[].
@@ -45,6 +45,84 @@ init_per_group(_GroupName, Config) ->
end_per_group(_GroupName, Config) ->
Config.
+do_async_dist(Dir) ->
+ X = 100,
+ AT = erlang:system_info(thread_pool_size),
+ Keys = file_keys(Dir,AT*X,[],[]),
+ Tab = ets:new(x,[ordered_set]),
+ [ ets:insert(Tab,{N,0}) || N <- lists:seq(0,AT-1) ],
+ [ ets:update_counter(Tab,(N rem AT),1) || N <- Keys ],
+ Res = [ V || {_,V} <- ets:tab2list(Tab) ],
+ ets:delete(Tab),
+ {Res, sdev(Res)/X}.
+
+sdev(List) ->
+ Len = length(List),
+ Mean = lists:sum(List)/Len,
+ math:sqrt(lists:sum([ (X - Mean) * (X - Mean) || X <- List ]) / Len).
+
+file_keys(_,0,FdList,FnList) ->
+ [ file:close(FD) || FD <- FdList ],
+ [ file:delete(FN) || FN <- FnList ],
+ [];
+file_keys(Dir,Num,FdList,FnList) ->
+ Name = "dummy"++integer_to_list(Num),
+ FN = filename:join([Dir,Name]),
+ case file:open(FN,[write,raw]) of
+ {ok,FD} ->
+ {file_descriptor,prim_file,{Port,_}} = FD,
+ <<X:32/integer-big>> =
+ iolist_to_binary(erlang:port_control(Port,$K,[])),
+ [X | file_keys(Dir,Num-1,[FD|FdList],[FN|FnList])];
+ {error,_} ->
+ % Try freeing up FD's if there are any
+ case FdList of
+ [] ->
+ exit({cannot_open_file,FN});
+ _ ->
+ [ file:close(FD) || FD <- FdList ],
+ [ file:delete(F) || F <- FnList ],
+ file_keys(Dir,Num,[],[])
+ end
+ end.
+
+async_dist(doc) ->
+ "Check that the distribution of files over async threads is fair";
+async_dist(Config) when is_list(Config) ->
+ DataDir = ?config(data_dir,Config),
+ TestFile = filename:join(DataDir, "existing_file"),
+ Dir = filename:dirname(code:which(?MODULE)),
+ AsyncSizes = [7,10,100,255,256,64,63,65],
+ Max = 0.5,
+
+ lists:foreach(fun(Size) ->
+ {ok,Node} =
+ test_server:start_node
+ (test_iter_max_files,slave,
+ [{args,
+ "+A "++integer_to_list(Size)++
+ " -pa " ++ Dir}]),
+ {Distr,SD} = rpc:call(Node,?MODULE,do_async_dist,
+ [DataDir]),
+ test_server:stop_node(Node),
+ if
+ SD > Max ->
+ io:format("Bad async queue distribution for "
+ "~p async threads:~n"
+ " Standard deviation is ~p~n"
+ " Key distribution:~n ~lp~n",
+ [Size,SD,Distr]),
+ exit({bad_async_dist,Size,SD,Distr});
+ true ->
+ io:format("OK async queue distribution for "
+ "~p async threads:~n"
+ " Standard deviation is ~p~n"
+ " Key distribution:~n ~lp~n",
+ [Size,SD,Distr]),
+ ok
+ end
+ end, AsyncSizes),
+ ok.
%%
%% Open as many files as possible. Do this several times and check
@@ -98,7 +176,7 @@ open_files(Name) ->
?line case file:open(Name, [read,raw]) of
{ok, Fd} ->
[Fd| open_files(Name)];
- {error, Reason} ->
-% io:format("Error reason: ~p", [Reason]),
+ {error, _Reason} ->
+% io:format("Error reason: ~p", [_Reason]),
[]
end.