MINOR: config: make the stream interface idle timer user-configurable

The new tune.idletimer value allows one to set a different value for
idle stream detection. The default value remains set to one second.
It is possible to disable it using zero, and to change the default
value at build time using DEFAULT_IDLE_TIMER.

doc/configuration.txt

@@ -481,6 +481,7 @@ The following keywords are supported in the "global" section :
    - tune.comp.maxlevel
    - tune.http.cookielen
    - tune.http.maxhdr
+   - tune.idletimer
    - tune.maxaccept
    - tune.maxpollevents
    - tune.maxrewrite
@@ -863,6 +864,17 @@ tune.http.maxhdr <number>
   new header consumes 32bits of memory for each session, so don't push this
   limit too high.
 
+tune.idletimer <timeout>
+  Sets the duration after which haproxy will consider that an empty buffer is
+  probably associated with an idle stream. This is used to optimally adjust
+  some packet sizes while forwarding large and small data alternatively. The
+  decision to use splice() or to send large buffers in SSL is modulated by this
+  parameter. The value is in milliseconds between 0 and 65535. A value of zero
+  means that haproxy will not try to detect idle streams. The default is 1000,
+  which seems to correctly detect end user pauses (eg: read a page before
+  clicking). There should be not reason for changing this value. Please check
+  tune.ssl.maxrecord below.
+
 tune.maxaccept <number>
   Sets the maximum number of consecutive connections a process may accept in a
   row before switching to other work. In single process mode, higher numbers
@@ -957,7 +969,8 @@ tune.ssl.maxrecord <number>
   Ethernet with TCP timestamps enabled, or 1460 when timestamps are disabled),
   keeping in mind that SSL/TLS add some overhead. Typical values of 1419 and
   2859 gave good results during tests. Use "strace -e trace=write" to find the
-  best value.
+  best value. Haproxy will automatically switch to this setting after an idle
+  stream has been detected (see tune.idletimer above).
 
 tune.zlib.memlevel <number>
   Sets the memLevel parameter in zlib initialization for each session. It

include/types/global.h

@@ -135,6 +135,7 @@ struct global {
 		int zlibwindowsize;  /* zlib window size */
 #endif
 		int comp_maxlevel;    /* max HTTP compression level */
+		unsigned short idle_timer; /* how long before an empty buffer is considered idle (ms) */
 	} tune;
 	struct {
 		char *prefix;           /* path prefix of unix bind socket */

src/cfgparse.c

@@ -618,6 +618,31 @@ int cfg_parse_global(const char *file, int linenum, char **args, int kwm)
 		if (global.tune.maxrewrite >= global.tune.bufsize / 2)
 			global.tune.maxrewrite = global.tune.bufsize / 2;
 	}
+	else if (!strcmp(args[0], "tune.idletimer")) {
+		unsigned int idle;
+		const char *res;
+
+		if (*(args[1]) == 0) {
+			Alert("parsing [%s:%d] : '%s' expects a timer value between 0 and 65535 ms.\n", file, linenum, args[0]);
+			err_code |= ERR_ALERT | ERR_FATAL;
+			goto out;
+		}
+
+		res = parse_time_err(args[1], &idle, TIME_UNIT_MS);
+		if (res) {
+			Alert("parsing [%s:%d]: unexpected character '%c' in argument to <%s>.\n",
+			      file, linenum, *res, args[0]);
+			err_code |= ERR_ALERT | ERR_FATAL;
+			goto out;
+		}
+
+		if (idle > 65535) {
+			Alert("parsing [%s:%d] : '%s' expects a timer value between 0 and 65535 ms.\n", file, linenum, args[0]);
+			err_code |= ERR_ALERT | ERR_FATAL;
+			goto out;
+		}
+		global.tune.idle_timer = idle;
+	}
 	else if (!strcmp(args[0], "tune.rcvbuf.client")) {
 		if (global.tune.client_rcvbuf != 0) {
 			Alert("parsing [%s:%d] : '%s' already specified. Continuing.\n", file, linenum, args[0]);

src/haproxy.c

@@ -151,8 +151,11 @@ struct global global = {
 		.zlibwindowsize = MAX_WBITS,
 #endif
 		.comp_maxlevel = 1,
-
-
+#ifdef DEFAULT_IDLE_TIMER
+		.idle_timer = DEFAULT_IDLE_TIMER,
+#else
+		.idle_timer = 1000, /* 1 second */
+#endif
 	},
 #ifdef USE_OPENSSL
 #ifdef DEFAULT_MAXSSLCONN

src/stream_interface.c

@@ -1097,7 +1097,8 @@ static void si_conn_recv_cb(struct connection *conn)
 	cur_read = 0;
 
 	if ((chn->flags & (CF_STREAMER | CF_STREAMER_FAST)) && !chn->buf->o &&
-	    (unsigned short)(now_ms - chn->last_read) >= 1000) {
+	    global.tune.idle_timer &&
+	    (unsigned short)(now_ms - chn->last_read) >= global.tune.idle_timer) {
 		/* The buffer was empty and nothing was transferred for more
 		 * than one second. This was caused by a pause and not by
 		 * congestion. Reset any streaming mode to reduce latency.