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authorAnthony Ramine <[email protected]>2013-04-05 11:47:02 +0200
committerAnthony Ramine <[email protected]>2013-04-11 14:28:45 +0200
commit9f2c736e273aed9034aeab2d2877b5c52cc8d327 (patch)
tree48aaedb3b41004bf8378ad6e7a5b33a5f437f782
parente72043e3519cb14aabf461849eba959b97e07410 (diff)
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Optimize communication with file io server
The file module communicates with a file io server with the following protocol for file operations: > {file_request,From,ReplyAs,Request} < {file_reply,ReplyAs,Reply} The ReplyAs value is sent by the client side to match against when receiving the reply and is otherwise left untouched and passed as is by the server. This commit enables receive optimizations by using the reference of the server monitor, changing the protocol to: > {file_request,From,MonitorRef,Request} < {file_reply,MonitorRef,Reply} As the shape of the messages is not changed, backwards compatibility is not a concern.
-rw-r--r--lib/kernel/src/file.erl43
-rw-r--r--lib/kernel/test/file_SUITE.erl29
2 files changed, 42 insertions, 30 deletions
diff --git a/lib/kernel/src/file.erl b/lib/kernel/src/file.erl
index a4c56b346f..36289053eb 100644
--- a/lib/kernel/src/file.erl
+++ b/lib/kernel/src/file.erl
@@ -480,8 +480,7 @@ open(Item, Mode) ->
Reason :: posix() | badarg | terminated.
close(File) when is_pid(File) ->
- R = file_request(File, close),
- case wait_file_reply(File, R) of
+ case file_request(File, close) of
{error, terminated} ->
ok;
Other ->
@@ -503,8 +502,7 @@ close(_) ->
Reason :: posix() | badarg.
advise(File, Offset, Length, Advise) when is_pid(File) ->
- R = file_request(File, {advise, Offset, Length, Advise}),
- wait_file_reply(File, R);
+ file_request(File, {advise, Offset, Length, Advise});
advise(#file_descriptor{module = Module} = Handle, Offset, Length, Advise) ->
Module:advise(Handle, Offset, Length, Advise);
advise(_, _, _, _) ->
@@ -517,8 +515,7 @@ advise(_, _, _, _) ->
Length :: non_neg_integer().
allocate(File, Offset, Length) when is_pid(File) ->
- R = file_request(File, {allocate, Offset, Length}),
- wait_file_reply(File, R);
+ file_request(File, {allocate, Offset, Length});
allocate(#file_descriptor{module = Module} = Handle, Offset, Length) ->
Module:allocate(Handle, Offset, Length).
@@ -601,8 +598,7 @@ pread_int(_, _, _) ->
Reason :: posix() | badarg | terminated.
pread(File, At, Sz) when is_pid(File), is_integer(Sz), Sz >= 0 ->
- R = file_request(File, {pread, At, Sz}),
- wait_file_reply(File, R);
+ file_request(File, {pread, At, Sz});
pread(#file_descriptor{module = Module} = Handle, Offs, Sz)
when is_integer(Sz), Sz >= 0 ->
Module:pread(Handle, Offs, Sz);
@@ -658,8 +654,7 @@ pwrite_int(_, _, _) ->
Reason :: posix() | badarg | terminated.
pwrite(File, At, Bytes) when is_pid(File) ->
- R = file_request(File, {pwrite, At, Bytes}),
- wait_file_reply(File, R);
+ file_request(File, {pwrite, At, Bytes});
pwrite(#file_descriptor{module = Module} = Handle, Offs, Bytes) ->
Module:pwrite(Handle, Offs, Bytes);
pwrite(_, _, _) ->
@@ -670,8 +665,7 @@ pwrite(_, _, _) ->
Reason :: posix() | badarg | terminated.
datasync(File) when is_pid(File) ->
- R = file_request(File, datasync),
- wait_file_reply(File, R);
+ file_request(File, datasync);
datasync(#file_descriptor{module = Module} = Handle) ->
Module:datasync(Handle);
datasync(_) ->
@@ -682,8 +676,7 @@ datasync(_) ->
Reason :: posix() | badarg | terminated.
sync(File) when is_pid(File) ->
- R = file_request(File, sync),
- wait_file_reply(File, R);
+ file_request(File, sync);
sync(#file_descriptor{module = Module} = Handle) ->
Module:sync(Handle);
sync(_) ->
@@ -696,8 +689,7 @@ sync(_) ->
Reason :: posix() | badarg | terminated.
position(File, At) when is_pid(File) ->
- R = file_request(File, {position,At}),
- wait_file_reply(File, R);
+ file_request(File, {position,At});
position(#file_descriptor{module = Module} = Handle, At) ->
Module:position(Handle, At);
position(_, _) ->
@@ -708,8 +700,7 @@ position(_, _) ->
Reason :: posix() | badarg | terminated.
truncate(File) when is_pid(File) ->
- R = file_request(File, truncate),
- wait_file_reply(File, R);
+ file_request(File, truncate);
truncate(#file_descriptor{module = Module} = Handle) ->
Module:truncate(Handle);
truncate(_) ->
@@ -1497,25 +1488,19 @@ check_args([]) ->
ok.
%%-----------------------------------------------------------------
-%% Functions for communicating with a file io server.
+%% Function for communicating with a file io server.
%% The messages sent have the following formats:
%%
%% {file_request,From,ReplyAs,Request}
%% {file_reply,ReplyAs,Reply}
file_request(Io, Request) ->
- R = erlang:monitor(process, Io),
- Io ! {file_request,self(),Io,Request},
- R.
-
-wait_file_reply(From, Ref) ->
+ Ref = erlang:monitor(process, Io),
+ Io ! {file_request,self(),Ref,Request},
receive
- {file_reply,From,Reply} ->
- erlang:demonitor(Ref),
- receive {'DOWN', Ref, _, _, _} -> ok after 0 -> ok end,
- %% receive {'EXIT', From, _} -> ok after 0 -> ok end,
+ {file_reply,Ref,Reply} ->
+ erlang:demonitor(Ref, [flush]),
Reply;
{'DOWN', Ref, _, _, _} ->
- %% receive {'EXIT', From, _} -> ok after 0 -> ok end,
{error, terminated}
end.
diff --git a/lib/kernel/test/file_SUITE.erl b/lib/kernel/test/file_SUITE.erl
index c604e7073f..4218cfa646 100644
--- a/lib/kernel/test/file_SUITE.erl
+++ b/lib/kernel/test/file_SUITE.erl
@@ -91,6 +91,8 @@
-export([standard_io/1,mini_server/1]).
+-export([old_io_protocol/1]).
+
%% Debug exports
-export([create_file_slow/2, create_file/2, create_bin/2]).
-export([verify_file/2, verify_bin/3]).
@@ -114,7 +116,7 @@ all() ->
delayed_write, read_ahead, segment_read, segment_write,
ipread, pid2name, interleaved_read_write, otp_5814, otp_10852,
large_file, large_write, read_line_1, read_line_2, read_line_3,
- read_line_4, standard_io].
+ read_line_4, standard_io, old_io_protocol].
groups() ->
[{dirs, [], [make_del_dir, cur_dir_0, cur_dir_1,
@@ -310,6 +312,31 @@ standard_io(Config) when is_list(Config) ->
Pid ! die,
receive after 1000 -> ok end.
+old_io_protocol(suite) ->
+ [];
+old_io_protocol(doc) ->
+ ["Test that the old file IO protocol =< R16B still works"];
+old_io_protocol(Config) when is_list(Config) ->
+ Dog = test_server:timetrap(test_server:seconds(5)),
+ RootDir = ?config(priv_dir,Config),
+ Name = filename:join(RootDir,
+ atom_to_list(?MODULE)
+ ++"old_io_protocol.fil"),
+ MyData = "0123456789abcdefghijklmnopqrstuvxyz",
+ ok = ?FILE_MODULE:write_file(Name, MyData),
+ {ok, Fd} = ?FILE_MODULE:open(Name, write),
+ Fd ! {file_request,self(),Fd,truncate},
+ receive
+ {file_reply,Fd,ok} -> ok
+ end,
+ ok = ?FILE_MODULE:close(Fd),
+ {ok, <<>>} = ?FILE_MODULE:read_file(Name),
+ test_server:timetrap_cancel(Dog),
+ [] = flush(),
+ ok.
+
+
+
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
read_write_file(suite) -> [];