for details.).</para></listitem>
</varlistentry>
+ <varlistentry>
+ <term><varname>DeferAccept=</varname></term>
+
+ <listitem><para>Takes time (in
+ seconds) as argument. If set, the
+ listening process will be awakened
+ only when data arrives on the socket,
+ and not immediately when connection is
+ established. When this option is set,
+ the
+ <constant>TCP_DEFER_ACCEPT</constant>
+ socket option will be used (see
+ <citerefentry><refentrytitle>tcp</refentrytitle><manvolnum>7</manvolnum></citerefentry>),
+ and the kernel will ignore initial ACK
+ packets without any data. The argument
+ specifies the approximate amount of
+ time the kernel should wait for
+ incoming data before falling back to
+ the normal behaviour of honouring
+ empty ACK packets. This option is
+ beneficial for protocols where the
+ client sends the data first (e.g.
+ HTTP, in contrast to SMTP), because
+ the server process will not be woken
+ up unnecessarily before it can take
+ any action.
+ </para>
+
+ <para>If the client also uses the
+ <constant>TCP_DEFER_ACCEPT</constant>
+ option, the latency of the initial
+ connection may be reduced, because the
+ kernel will send data in the final
+ packet establishing the connection
+ (the third packet in the "three-way
+ handshake").</para>
+
+ <para>Disabled by default.</para>
+ </listitem>
+ </varlistentry>
+
<varlistentry>
<term><varname>ReceiveBuffer=</varname></term>
<term><varname>SendBuffer=</varname></term>
SD_BUS_PROPERTY("KeepAliveTime", "t", bus_property_get_usec, offsetof(Socket, keep_alive_time), SD_BUS_VTABLE_PROPERTY_CONST),
SD_BUS_PROPERTY("KeepAliveInterval", "t", bus_property_get_usec, offsetof(Socket, keep_alive_interval), SD_BUS_VTABLE_PROPERTY_CONST),
SD_BUS_PROPERTY("KeepAliveProbes", "u", bus_property_get_unsigned, offsetof(Socket, keep_alive_cnt), SD_BUS_VTABLE_PROPERTY_CONST),
+ SD_BUS_PROPERTY("DeferAccept" , "t", bus_property_get_usec, offsetof(Socket, defer_accept), SD_BUS_VTABLE_PROPERTY_CONST),
SD_BUS_PROPERTY("Priority", "i", bus_property_get_int, offsetof(Socket, priority), SD_BUS_VTABLE_PROPERTY_CONST),
SD_BUS_PROPERTY("ReceiveBuffer", "t", bus_property_get_size, offsetof(Socket, receive_buffer), SD_BUS_VTABLE_PROPERTY_CONST),
SD_BUS_PROPERTY("SendBuffer", "t", bus_property_get_size, offsetof(Socket, send_buffer), SD_BUS_VTABLE_PROPERTY_CONST),
Socket.KeepAliveTime, config_parse_sec, 0, offsetof(Socket, keep_alive_time)
Socket.KeepAliveInterval, config_parse_sec, 0, offsetof(Socket, keep_alive_interval)
Socket.KeepAliveProbes, config_parse_unsigned, 0, offsetof(Socket, keep_alive_cnt)
+Socket.DeferAccept, config_parse_sec, 0, offsetof(Socket, defer_accept)
Socket.NoDelay, config_parse_bool, 0, offsetof(Socket, no_delay)
Socket.Priority, config_parse_int, 0, offsetof(Socket, priority)
Socket.ReceiveBuffer, config_parse_iec_size, 0, offsetof(Socket, receive_buffer)
"%sKeepAliveProbes: %u\n",
prefix, s->keep_alive_cnt);
+ if(s->defer_accept)
+ fprintf(f,
+ "%sDeferAccept: %s\n",
+ prefix, format_timespan(time_string, FORMAT_TIMESPAN_MAX,
+ s->defer_accept, USEC_PER_SEC));
+
LIST_FOREACH(port, p, s->ports) {
if (p->type == SOCKET_SOCKET) {
log_warning_unit(UNIT(s)->id, "TCP_KEEPCNT failed: %m");
}
+ if (s->defer_accept) {
+ int value = s->defer_accept / USEC_PER_SEC;
+ if (setsockopt(fd, SOL_TCP, TCP_DEFER_ACCEPT, &value, sizeof(value)) < 0)
+ log_warning_unit(UNIT(s)->id, "TCP_DEFER_ACCEPT failed: %m");
+ }
+
if (s->no_delay) {
int b = s->no_delay;
if (setsockopt(fd, SOL_TCP, TCP_NODELAY, &b, sizeof(b)) < 0)
usec_t timeout_usec;
usec_t keep_alive_time;
usec_t keep_alive_interval;
+ usec_t defer_accept;
ExecCommand* exec_command[_SOCKET_EXEC_COMMAND_MAX];
ExecContext exec_context;