diff options
| -rw-r--r-- | lib/stdlib/doc/src/io_protocol.xml | 7 | ||||
| -rw-r--r-- | lib/stdlib/src/io.erl | 43 | ||||
| -rw-r--r-- | lib/stdlib/test/io_SUITE.erl | 46 |
3 files changed, 65 insertions, 31 deletions
diff --git a/lib/stdlib/doc/src/io_protocol.xml b/lib/stdlib/doc/src/io_protocol.xml index 0b76882da4..21da404c35 100644 --- a/lib/stdlib/doc/src/io_protocol.xml +++ b/lib/stdlib/doc/src/io_protocol.xml @@ -76,10 +76,11 @@ the server eventually sends a corresponding <c>io_reply</c> tuple.</p> the I/O server sends the IO reply to.</item> <item><c>ReplyAs</c> can be any datum and is returned in the corresponding -<c>io_reply</c>. The <seealso marker="stdlib:io">io</seealso> module simply uses the pid() -of the I/O server as the <c>ReplyAs</c> datum, but a more complicated client +<c>io_reply</c>. The <seealso marker="stdlib:io">io</seealso> module monitors +the I/O server, and uses the monitor reference as the <c>ReplyAs</c> datum. +A more complicated client could have several outstanding I/O requests to the same I/O server and -would then use i.e. a <c>reference()</c> or something else to differentiate among +would then use different references (or something else) to differentiate among the incoming IO replies. The <c>ReplyAs</c> element should be considered opaque by the I/O server. Note that the <c>pid()</c> of the I/O server is not explicitly present in the <c>io_reply</c> tuple. The reply can be sent from any diff --git a/lib/stdlib/src/io.erl b/lib/stdlib/src/io.erl index 27e2a82b41..b9ace2f442 100644 --- a/lib/stdlib/src/io.erl +++ b/lib/stdlib/src/io.erl @@ -566,12 +566,23 @@ request(Name, Request) when is_atom(Name) -> execute_request(Pid, {Convert,Converted}) -> Mref = erlang:monitor(process, Pid), - Pid ! {io_request,self(),Pid,Converted}, - if - Convert -> - convert_binaries(wait_io_mon_reply(Pid, Mref)); - true -> - wait_io_mon_reply(Pid, Mref) + Pid ! {io_request,self(),Mref,Converted}, + + receive + {io_reply, Mref, Reply} -> + erlang:demonitor(Mref, [flush]), + if + Convert -> + convert_binaries(Reply); + true -> + Reply + end; + {'DOWN', Mref, _, _, _} -> + receive + {'EXIT', Pid, _What} -> true + after 0 -> true + end, + {error,terminated} end. requests(Requests) -> %Requests as atomic action @@ -597,26 +608,6 @@ default_input() -> default_output() -> group_leader(). -wait_io_mon_reply(From, Mref) -> - receive - {io_reply, From, Reply} -> - erlang:demonitor(Mref, [flush]), - Reply; - {'EXIT', From, _What} -> - receive - {'DOWN', Mref, _, _, _} -> true - after 0 -> true - end, - {error,terminated}; - {'DOWN', Mref, _, _, _} -> - receive - {'EXIT', From, _What} -> true - after 0 -> true - end, - {error,terminated} - end. - - %% io_requests(Requests) %% Transform requests into correct i/o server messages. Only handle the %% one we KNOW must be changed, others, including incorrect ones, are diff --git a/lib/stdlib/test/io_SUITE.erl b/lib/stdlib/test/io_SUITE.erl index 3a76275f31..2203dd8f51 100644 --- a/lib/stdlib/test/io_SUITE.erl +++ b/lib/stdlib/test/io_SUITE.erl @@ -30,7 +30,8 @@ io_fread_newlines/1, otp_8989/1, io_lib_fread_literal/1, printable_range/1, io_lib_print_binary_depth_one/1, otp_10302/1, otp_10755/1, - otp_10836/1, io_lib_width_too_small/1]). + otp_10836/1, io_lib_width_too_small/1, + io_with_huge_message_queue/1]). -export([pretty/2]). @@ -70,7 +71,7 @@ all() -> io_fread_newlines, otp_8989, io_lib_fread_literal, printable_range, io_lib_print_binary_depth_one, otp_10302, otp_10755, otp_10836, - io_lib_width_too_small]. + io_lib_width_too_small, io_with_huge_message_queue]. groups() -> []. @@ -2219,3 +2220,44 @@ io_lib_width_too_small(Config) -> "**" = lists:flatten(io_lib:format("~2.3w", [3.14])), "**" = lists:flatten(io_lib:format("~2.5w", [3.14])), ok. + +%% Test that the time for a huge message queue is not +%% significantly slower than with an empty message queue. +io_with_huge_message_queue(Config) when is_list(Config) -> + case test_server:is_native(gen) of + true -> + {skip, + "gen is native - huge message queue optimization " + "is not implemented"}; + false -> + do_io_with_huge_message_queue(Config) + end. + +do_io_with_huge_message_queue(Config) -> + PrivDir = ?privdir(Config), + File = filename:join(PrivDir, "slask"), + {ok, F1} = file:open(File, [write]), + + {Time,ok} = timer:tc(fun() -> writes(1000, F1) end), + + [self() ! {msg,N} || N <- lists:seq(1, 500000)], + erlang:garbage_collect(), + {NewTime,ok} = timer:tc(fun() -> writes(1000, F1) end), + file:close(F1), + io:format("Time for empty message queue: ~p", [Time]), + io:format("Time for huge message queue: ~p", [NewTime]), + + IsCover = test_server:is_cover(), + case (NewTime+1) / (Time+1) of + Q when Q < 10; IsCover -> + ok; + Q -> + io:format("Q = ~p", [Q]), + ?t:fail() + end, + ok. + +writes(0, _) -> ok; +writes(N, F1) -> + file:write(F1, "hello\n"), + writes(N - 1, F1). |