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authorMagnus Henoch <[email protected]>2014-06-27 17:57:04 +0100
committerMagnus Henoch <[email protected]>2014-09-19 18:48:12 +0100
commit69e8387629bdea141e196c515f4d9381f7ac3e18 (patch)
treefb9843a0e7828942c289df7a689b64238c7f8338 /lib/stdlib/src
parent6ec976bd70a657efea2d5d714e0d470aeb86bb50 (diff)
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Optimise io requests for long message queues
Ensure that the monitor reference is present in all receive clauses, so that the compiler optimisation kicks in and the run time won't depend on the length of the message queue of the calling process. Remove the 'EXIT' clause, as its presence breaks the optimisation, and that case is handled by the 'DOWN' clause anyway. The test io_SUITE:io_with_huge_message_queue is an adaptation of gen_server_SUITE:call_with_huge_message_queue.
Diffstat (limited to 'lib/stdlib/src')
-rw-r--r--lib/stdlib/src/io.erl43
1 files changed, 17 insertions, 26 deletions
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