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authorIgor Slepchin <[email protected]>2018-09-24 22:44:03 -0400
committerIgor Slepchin <[email protected]>2018-10-11 01:07:19 -0400
commit210665e8a252faecf28ccebade999e734ab92582 (patch)
tree8b81350cb43fd9a59ea13e34e03017f82fccbef3 /lib
parent3daef1a4ee8cfce90d0220be3695809ccbb8ea58 (diff)
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Add nopush TCP socket option
This translates to TCP_CORK on Linux and TCP_NOPUSH on BSD. In effect, this acts as super-Nagle: no partial TCP segments are sent out until this option is turned off. Once turned off, all accumulated unsent data is sent out immediately. The latter is *not* the case on OSX, hence the implementation ignores "nopush" on OSX to reduce confusion.
Diffstat (limited to 'lib')
-rw-r--r--lib/kernel/doc/src/inet.xml12
-rw-r--r--lib/kernel/src/inet_int.hrl1
-rw-r--r--lib/kernel/test/inet_sockopt_SUITE.erl9
3 files changed, 20 insertions, 2 deletions
diff --git a/lib/kernel/doc/src/inet.xml b/lib/kernel/doc/src/inet.xml
index ed775d67eb..9fc361a234 100644
--- a/lib/kernel/doc/src/inet.xml
+++ b/lib/kernel/doc/src/inet.xml
@@ -1039,6 +1039,18 @@ setcap cap_sys_admin,cap_sys_ptrace,cap_dac_read_search+epi beam.smp</code>
is turned on for the socket, which means that also small
amounts of data are sent immediately.</p>
</item>
+ <tag><c>{nopush, Boolean}</c>(TCP/IP sockets)</tag>
+ <item>
+ <p>This translates to <c>TCP_NOPUSH</c> on BSD and
+ to <c>TCP_CORK</c> on Linux.</p>
+ <p>If <c>Boolean == true</c>, the corresponding option
+ is turned on for the socket, which means that small
+ amounts of data are accumulated until a full MSS-worth
+ of data is available or this option is turned off.</p>
+ <p>Note that while <c>TCP_NOPUSH</c> socket option is available on OSX, its semantics
+ is very different (e.g., unsetting it does not cause immediate send
+ of accumulated data). Hence, <c>nopush</c> option is intentionally ignored on OSX.</p>
+ </item>
<tag><c>{packet, PacketType}</c>(TCP/IP sockets)</tag>
<item>
<p><marker id="packet"/>Defines the type of packets to use for a socket.
diff --git a/lib/kernel/src/inet_int.hrl b/lib/kernel/src/inet_int.hrl
index c8e09d18ad..f6525d7261 100644
--- a/lib/kernel/src/inet_int.hrl
+++ b/lib/kernel/src/inet_int.hrl
@@ -162,6 +162,7 @@
-define(INET_OPT_PKTOPTIONS, 45).
-define(INET_OPT_TTL, 46).
-define(INET_OPT_RECVTTL, 47).
+-define(TCP_OPT_NOPUSH, 48).
% Specific SCTP options: separate range:
-define(SCTP_OPT_RTOINFO, 100).
-define(SCTP_OPT_ASSOCINFO, 101).
diff --git a/lib/kernel/test/inet_sockopt_SUITE.erl b/lib/kernel/test/inet_sockopt_SUITE.erl
index ada9c2689c..27ff74e309 100644
--- a/lib/kernel/test/inet_sockopt_SUITE.erl
+++ b/lib/kernel/test/inet_sockopt_SUITE.erl
@@ -110,9 +110,14 @@ simple(Config) when is_list(Config) ->
{S1,S2} = create_socketpair(Opt, Opt),
{ok,Opt} = inet:getopts(S1,OptTags),
{ok,Opt} = inet:getopts(S2,OptTags),
- COpt = [{X,case X of nodelay -> false;_ -> Y end} || {X,Y} <- Opt],
+ NoPushOpt = case os:type() of
+ {unix, Osname} when Osname =:= linux; Osname =:= freebsd -> {nopush, true};
+ {_,_} -> {nopush, false}
+ end,
+ COpt = [{X,case X of nodelay -> false;_ -> Y end} || {X,Y} <- [NoPushOpt|Opt]],
+ COptTags = [X || {X,_} <- COpt],
inet:setopts(S1,COpt),
- {ok,COpt} = inet:getopts(S1,OptTags),
+ {ok,COpt} = inet:getopts(S1,COptTags),
{ok,Opt} = inet:getopts(S2,OptTags),
gen_tcp:close(S1),
gen_tcp:close(S2),