From 44364d7112037bebb0bb1d20f72b12b1f736fa95 Mon Sep 17 00:00:00 2001
From: nicm <nicm>
Date: Mon, 11 May 2015 10:10:16 +0000
Subject: [PATCH 1/6] Remove the c0-* options which never really worked
 satisfactorily. Going to try something else...

---
 input.c  | 16 +++-------------
 tmux.1   | 18 ------------------
 tmux.h   |  5 -----
 window.c | 40 ----------------------------------------
 4 files changed, 3 insertions(+), 76 deletions(-)

diff --git a/input.c b/input.c
index 384ab45d..886d561d 100644
--- a/input.c
+++ b/input.c
@@ -1069,7 +1069,6 @@ input_c0_dispatch(struct input_ctx *ictx)
 	struct screen_write_ctx	*sctx = &ictx->ctx;
 	struct window_pane	*wp = ictx->wp;
 	struct screen		*s = sctx->s;
-	u_int			 trigger;
 
 	log_debug("%s: '%c", __func__, ictx->ch);
 
@@ -1081,7 +1080,7 @@ input_c0_dispatch(struct input_ctx *ictx)
 		break;
 	case '\010':	/* BS */
 		screen_write_backspace(sctx);
-		goto count_c0;
+		break;
 	case '\011':	/* HT */
 		/* Don't tab beyond the end of the line. */
 		if (s->cx >= screen_size_x(s) - 1)
@@ -1098,10 +1097,10 @@ input_c0_dispatch(struct input_ctx *ictx)
 	case '\013':	/* VT */
 	case '\014':	/* FF */
 		screen_write_linefeed(sctx, 0);
-		goto count_c0;
+		break;
 	case '\015':	/* CR */
 		screen_write_carriagereturn(sctx);
-		goto count_c0;
+		break;
 	case '\016':	/* SO */
 		ictx->cell.set = 1;
 		break;
@@ -1113,15 +1112,6 @@ input_c0_dispatch(struct input_ctx *ictx)
 		break;
 	}
 
-	return (0);
-
-count_c0:
-	trigger = options_get_number(&wp->window->options, "c0-change-trigger");
-	if (trigger != 0 && ++wp->changes >= trigger) {
-		wp->flags |= PANE_DROP;
-		window_pane_timer_start(wp);
-	}
-
 	return (0);
 }
 
diff --git a/tmux.1 b/tmux.1
index 9debeaf4..79dfa4b4 100644
--- a/tmux.1
+++ b/tmux.1
@@ -2886,24 +2886,6 @@ used when the
 .Ic automatic-rename
 option is enabled.
 .Pp
-.It Ic c0-change-interval Ar interval
-.It Ic c0-change-trigger Ar trigger
-These two options configure a simple form of rate limiting for a pane.
-If
-.Nm
-sees more than
-.Ar trigger
-C0 sequences that modify the screen (for example, carriage returns, linefeeds
-or backspaces) in one millisecond, it will stop updating the pane immediately and
-instead redraw it entirely every
-.Ar interval
-milliseconds.
-This helps to prevent fast output (such as
-.Xr yes 1 )
-overwhelming the terminal.
-The default is a trigger of 250 and an interval of 100.
-A trigger of zero disables the rate limiting.
-.Pp
 .It Ic clock-mode-colour Ar colour
 Set clock colour.
 .Pp
diff --git a/tmux.h b/tmux.h
index 6d4e29fd..ccbdb763 100644
--- a/tmux.h
+++ b/tmux.h
@@ -844,10 +844,6 @@ struct window_pane {
 	char		 tty[TTY_NAME_MAX];
 	int		 status;
 
-	u_int		 changes;
-	struct event	 changes_timer;
-	u_int		 changes_redraw;
-
 	int		 fd;
 	struct bufferevent *event;
 
@@ -2107,7 +2103,6 @@ struct window_pane *window_pane_find_by_id_str(const char *);
 struct window_pane *window_pane_find_by_id(u_int);
 struct window_pane *window_pane_create(struct window *, u_int, u_int, u_int);
 void		 window_pane_destroy(struct window_pane *);
-void		 window_pane_timer_start(struct window_pane *);
 int		 window_pane_spawn(struct window_pane *, int, char **,
 		     const char *, const char *, int, struct environ *,
 		     struct termios *, char **);
diff --git a/window.c b/window.c
index 8366833a..7edfed42 100644
--- a/window.c
+++ b/window.c
@@ -58,7 +58,6 @@ u_int	next_window_pane_id;
 u_int	next_window_id;
 u_int	next_active_point;
 
-void	window_pane_timer_callback(int, short, void *);
 void	window_pane_read_callback(struct bufferevent *, void *);
 void	window_pane_error_callback(struct bufferevent *, short, void *);
 
@@ -741,9 +740,6 @@ window_pane_destroy(struct window_pane *wp)
 {
 	window_pane_reset_mode(wp);
 
-	if (event_initialized(&wp->changes_timer))
-		evtimer_del(&wp->changes_timer);
-
 	if (wp->fd != -1) {
 		bufferevent_free(wp->event);
 		close(wp->fd);
@@ -877,42 +873,6 @@ window_pane_spawn(struct window_pane *wp, int argc, char **argv,
 	return (0);
 }
 
-void
-window_pane_timer_start(struct window_pane *wp)
-{
-	struct timeval	tv;
-
-	tv.tv_sec = 0;
-	tv.tv_usec = 1000;
-
-	evtimer_del(&wp->changes_timer);
-	evtimer_set(&wp->changes_timer, window_pane_timer_callback, wp);
-	evtimer_add(&wp->changes_timer, &tv);
-}
-
-void
-window_pane_timer_callback(unused int fd, unused short events, void *data)
-{
-	struct window_pane	*wp = data;
-	struct window		*w = wp->window;
-	u_int			 interval, trigger;
-
-	interval = options_get_number(&w->options, "c0-change-interval");
-	trigger = options_get_number(&w->options, "c0-change-trigger");
-
-	if (wp->changes_redraw++ == interval) {
-		wp->flags |= PANE_REDRAW;
-		wp->changes_redraw = 0;
-	}
-
-	if (trigger == 0 || wp->changes < trigger) {
-		wp->flags |= PANE_REDRAW;
-		wp->flags &= ~PANE_DROP;
-	} else
-		window_pane_timer_start(wp);
-	wp->changes = 0;
-}
-
 void
 window_pane_read_callback(unused struct bufferevent *bufev, void *data)
 {

From b833fabeb2334c44406bd54ff7cc804d20c546f6 Mon Sep 17 00:00:00 2001
From: nicm <nicm>
Date: Mon, 11 May 2015 10:58:22 +0000
Subject: [PATCH 2/6] Left the c0-* options behind in the table.

---
 options-table.c | 14 --------------
 1 file changed, 14 deletions(-)

diff --git a/options-table.c b/options-table.c
index 21758543..9869e14f 100644
--- a/options-table.c
+++ b/options-table.c
@@ -485,20 +485,6 @@ const struct options_table_entry window_options_table[] = {
 	                 "#{?pane_dead,[dead],}"
 	},
 
-	{ .name = "c0-change-trigger",
-	  .type = OPTIONS_TABLE_NUMBER,
-	  .default_num = 250,
-	  .minimum = 0,
-	  .maximum = USHRT_MAX
-	},
-
-	{ .name = "c0-change-interval",
-	  .type = OPTIONS_TABLE_NUMBER,
-	  .default_num = 100,
-	  .minimum = 1,
-	  .maximum = USHRT_MAX
-	},
-
 	{ .name = "clock-mode-colour",
 	  .type = OPTIONS_TABLE_COLOUR,
 	  .default_num = 4

From e958db09a72c2308d3edc8384be02714eb068ae7 Mon Sep 17 00:00:00 2001
From: nicm <nicm>
Date: Tue, 12 May 2015 15:27:46 +0000
Subject: [PATCH 3/6] Add bell-action "other" to pass through bells in all
 windows except the current, suggested by Jan ONDREJ.

---
 options-table.c |  2 +-
 server-window.c | 11 ++++++++---
 tmux.1          |  8 +++++---
 tmux.h          |  1 +
 4 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/options-table.c b/options-table.c
index 9869e14f..44d36dca 100644
--- a/options-table.c
+++ b/options-table.c
@@ -49,7 +49,7 @@ const char *options_table_status_position_list[] = {
 	"top", "bottom", NULL
 };
 const char *options_table_bell_action_list[] = {
-	"none", "any", "current", NULL
+	"none", "any", "current", "other", NULL
 };
 
 /* Server options. */
diff --git a/server-window.c b/server-window.c
index 4385dd90..1b3938d3 100644
--- a/server-window.c
+++ b/server-window.c
@@ -77,13 +77,18 @@ server_window_check_bell(struct session *s, struct winlink *wl)
 		if (c->session != s || c->flags & CLIENT_CONTROL)
 			continue;
 		if (!visual) {
-			if (c->session->curw->window == w || action == BELL_ANY)
+			if ((action == BELL_CURRENT &&
+			    c->session->curw->window == w) ||
+			    (action == BELL_OTHER &&
+			    c->session->curw->window != w) ||
+			    action == BELL_ANY)
 				tty_bell(&c->tty);
 			continue;
 		}
-		if (c->session->curw->window == w)
+		if (action == BELL_CURRENT && c->session->curw->window == w)
 			status_message_set(c, "Bell in current window");
-		else if (action == BELL_ANY)
+		else if (action == BELL_ANY || (action == BELL_OTHER &&
+		    c->session->curw->window != w))
 			status_message_set(c, "Bell in window %d", wl->idx);
 	}
 
diff --git a/tmux.1 b/tmux.1
index 79dfa4b4..7d9c0dc8 100644
--- a/tmux.1
+++ b/tmux.1
@@ -2375,16 +2375,18 @@ Set the base index from which an unused index should be searched when a new
 window is created.
 The default is zero.
 .It Xo Ic bell-action
-.Op Ic any | none | current
+.Op Ic any | none | current | other
 .Xc
 Set action on window bell.
 .Ic any
 means a bell in any window linked to a session causes a bell in the current
 window of that session,
 .Ic none
-means all bells are ignored and
+means all bells are ignored,
 .Ic current
-means only bells in windows other than the current window are ignored.
+means only bells in windows other than the current window are ignored and
+.Ic other
+means bells in the current window are ignored but not those in other windows.
 .It Xo Ic bell-on-alert
 .Op Ic on | off
 .Xc
diff --git a/tmux.h b/tmux.h
index ccbdb763..f7c44b20 100644
--- a/tmux.h
+++ b/tmux.h
@@ -75,6 +75,7 @@ extern char   **environ;
 #define BELL_NONE 0
 #define BELL_ANY 1
 #define BELL_CURRENT 2
+#define BELL_OTHER 3
 
 /* Special key codes. */
 #define KEYC_NONE 0xfff

From ec34439f9cddcbde78d5fa2c628e454d2df5dd53 Mon Sep 17 00:00:00 2001
From: nicm <nicm>
Date: Tue, 12 May 2015 15:29:29 +0000
Subject: [PATCH 4/6] Add a session_alerts format which is a list of all the
 alerts in the current session in symbolic form (something like "0!,4~,5!").
 Use this in the default set-titles-string. Prompted by a request from Jan
 ONDREJ.

---
 format.c        | 20 ++++++++++++++++++++
 options-table.c |  2 +-
 tmux.1          |  1 +
 3 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/format.c b/format.c
index 39351fc3..db6f9231 100644
--- a/format.c
+++ b/format.c
@@ -494,6 +494,8 @@ format_defaults_session(struct format_tree *ft, struct session *s)
 {
 	struct session_group	*sg;
 	time_t			 t;
+	struct winlink		*wl;
+	char			 alerts[256], tmp[16];
 
 	ft->s = s;
 
@@ -518,6 +520,24 @@ format_defaults_session(struct format_tree *ft, struct session *s)
 
 	format_add(ft, "session_attached", "%u", s->attached);
 	format_add(ft, "session_many_attached", "%d", s->attached > 1);
+
+	*alerts = '\0';
+	RB_FOREACH (wl, winlinks, &s->windows) {
+		if ((wl->flags & WINLINK_ALERTFLAGS) == 0)
+			continue;
+		snprintf(tmp, sizeof tmp, "%u", wl->idx);
+
+		if (*alerts != '\0')
+			strlcat(alerts, ",", sizeof alerts);
+		strlcat(alerts, tmp, sizeof alerts);
+		if (wl->flags & WINLINK_ACTIVITY)
+			strlcat(alerts, "#", sizeof alerts);
+		if (wl->flags & WINLINK_BELL)
+			strlcat(alerts, "!", sizeof alerts);
+		if (wl->flags & WINLINK_SILENCE)
+			strlcat(alerts, "~", sizeof alerts);
+	}
+	format_add(ft, "session_alerts", "%s", alerts);
 }
 
 /* Set default format keys for a client. */
diff --git a/options-table.c b/options-table.c
index 44d36dca..4ad45d37 100644
--- a/options-table.c
+++ b/options-table.c
@@ -296,7 +296,7 @@ const struct options_table_entry session_options_table[] = {
 
 	{ .name = "set-titles-string",
 	  .type = OPTIONS_TABLE_STRING,
-	  .default_str = "#S:#I:#W - \"#T\""
+	  .default_str = "#S:#I:#W - \"#T\" #{session_alerts}"
 	},
 
 	{ .name = "status",
diff --git a/tmux.1 b/tmux.1
index 7d9c0dc8..f5a0aaa3 100644
--- a/tmux.1
+++ b/tmux.1
@@ -3304,6 +3304,7 @@ The following variables are available, where appropriate:
 .It Li "pane_width" Ta "" Ta "Width of pane"
 .It Li "scroll_region_lower" Ta "" Ta "Bottom of scroll region in pane"
 .It Li "scroll_region_upper" Ta "" Ta "Top of scroll region in pane"
+.It Li "session_alerts" Ta "" Ta "List of window indexes with alerts"
 .It Li "session_attached" Ta "" Ta "Number of clients session is attached to"
 .It Li "session_activity" Ta "" Ta "Integer time of session last activity"
 .It Li "session_activity_string" Ta "" Ta "String time of session last activity"

From 37ae8a9e0fc2cd7ab2387a9a762a39dc0ff6723c Mon Sep 17 00:00:00 2001
From: nicm <nicm>
Date: Tue, 12 May 2015 19:36:08 +0000
Subject: [PATCH 5/6] Tidy blank lines when outputting server info.

---
 cmd-show-messages.c | 48 +++++++++++++++++++++++++--------------------
 1 file changed, 27 insertions(+), 21 deletions(-)

diff --git a/cmd-show-messages.c b/cmd-show-messages.c
index 028b4bb0..2a04bd93 100644
--- a/cmd-show-messages.c
+++ b/cmd-show-messages.c
@@ -47,11 +47,11 @@ const struct cmd_entry cmd_server_info_entry = {
 	cmd_show_messages_exec
 };
 
-void	cmd_show_messages_server(struct cmd_q *);
-void	cmd_show_messages_terminals(struct cmd_q *);
-void	cmd_show_messages_jobs(struct cmd_q *);
+int	cmd_show_messages_server(struct cmd_q *);
+int	cmd_show_messages_terminals(struct cmd_q *, int);
+int	cmd_show_messages_jobs(struct cmd_q *, int);
 
-void
+int
 cmd_show_messages_server(struct cmd_q *cmdq)
 {
 	char	*tim;
@@ -63,10 +63,12 @@ cmd_show_messages_server(struct cmd_q *cmdq)
 	cmdq_print(cmdq, "socket path %s", socket_path);
 	cmdq_print(cmdq, "debug level %d", debug_level);
 	cmdq_print(cmdq, "protocol version %d", PROTOCOL_VERSION);
+
+	return (1);
 }
 
-void
-cmd_show_messages_terminals(struct cmd_q *cmdq)
+int
+cmd_show_messages_terminals(struct cmd_q *cmdq, int blank)
 {
 	struct tty_term				*term;
 	const struct tty_term_code_entry	*ent;
@@ -76,8 +78,11 @@ cmd_show_messages_terminals(struct cmd_q *cmdq)
 
 	n = 0;
 	LIST_FOREACH(term, &tty_terms, entry) {
-		cmdq_print(cmdq,
-		    "Terminal %u: %s [references=%u, flags=0x%x]:",
+		if (blank) {
+			cmdq_print(cmdq, "%s", "");
+			blank = 0;
+		}
+		cmdq_print(cmdq, "Terminal %u: %s [references=%u, flags=0x%x]:",
 		    n, term->name, term->references, term->flags);
 		n++;
 		for (i = 0; i < NTTYCODE; i++) {
@@ -106,21 +111,26 @@ cmd_show_messages_terminals(struct cmd_q *cmdq)
 			}
 		}
 	}
+	return (n != 0);
 }
 
-void
-cmd_show_messages_jobs(struct cmd_q *cmdq)
+int
+cmd_show_messages_jobs(struct cmd_q *cmdq, int blank)
 {
 	struct job	*job;
 	u_int		 n;
 
 	n = 0;
 	LIST_FOREACH(job, &all_jobs, lentry) {
-		cmdq_print(cmdq,
-		    "Job %u: %s [fd=%d, pid=%d, status=%d]",
+		if (blank) {
+			cmdq_print(cmdq, "%s", "");
+			blank = 0;
+		}
+		cmdq_print(cmdq, "Job %u: %s [fd=%d, pid=%d, status=%d]",
 		    n, job->cmd, job->fd, job->pid, job->status);
 		n++;
 	}
+	return (n != 0);
 }
 
 enum cmd_retval
@@ -130,23 +140,19 @@ cmd_show_messages_exec(struct cmd *self, struct cmd_q *cmdq)
 	struct client		*c;
 	struct message_entry	*msg;
 	char			*tim;
-	int			 done;
+	int			 done, blank;
 
-	done = 0;
+	done = blank = 0;
 	if (args_has(args, 'I') || self->entry == &cmd_server_info_entry) {
-		cmd_show_messages_server(cmdq);
+		blank = cmd_show_messages_server(cmdq);
 		done = 1;
 	}
 	if (args_has(args, 'T') || self->entry == &cmd_server_info_entry) {
-		if (done)
-			cmdq_print(cmdq, "%s", "");
-		cmd_show_messages_terminals(cmdq);
+		blank = cmd_show_messages_terminals(cmdq, blank);
 		done = 1;
 	}
 	if (args_has(args, 'J') || self->entry == &cmd_server_info_entry) {
-		if (done)
-			cmdq_print(cmdq, "%s", "");
-		cmd_show_messages_jobs(cmdq);
+		cmd_show_messages_jobs(cmdq, blank);
 		done = 1;
 	}
 	if (done)

From 3f4ee98162cd5bb7000f93fec0e631e123b1281d Mon Sep 17 00:00:00 2001
From: nicm <nicm>
Date: Tue, 12 May 2015 22:40:38 +0000
Subject: [PATCH 6/6] To replace c0-*, add a high watermark to the pty event,
 and also backoff when the any of the ttys the pane is going to write to has
 buffered enough data.

---
 tmux.h   | 16 ++++++++++++++--
 tty.c    | 26 +++++++++++++++++---------
 window.c | 56 ++++++++++++++++++++++++++++++++++++++++++++++++--------
 3 files changed, 79 insertions(+), 19 deletions(-)

diff --git a/tmux.h b/tmux.h
index f7c44b20..bc47a268 100644
--- a/tmux.h
+++ b/tmux.h
@@ -56,6 +56,16 @@ extern char   **environ;
  */
 #define UTF8_SIZE 9
 
+/*
+ * READ_SIZE is the maximum size of data to hold from a pty (the event high
+ * watermark). READ_BACKOFF is the amount of data waiting to be output to a tty
+ * before pty reads will be backed off. READ_TIME is how long to back off
+ * before the next read (in microseconds) if a tty is above READ_BACKOFF.
+ */
+#define READ_SIZE 1024
+#define READ_BACKOFF 512
+#define READ_TIME 100
+
 /* Fatal errors. */
 #define fatal(msg) log_fatal("%s: %s", __func__, msg);
 #define fatalx(msg) log_fatalx("%s: %s", __func__, msg);
@@ -847,6 +857,7 @@ struct window_pane {
 
 	int		 fd;
 	struct bufferevent *event;
+	struct event	 timer;
 
 	struct input_ctx *ictx;
 
@@ -1595,8 +1606,9 @@ void	tty_draw_line(struct tty *, const struct window_pane *, struct screen *,
 int	tty_open(struct tty *, char **);
 void	tty_close(struct tty *);
 void	tty_free(struct tty *);
-void	tty_write(
-	    void (*)(struct tty *, const struct tty_ctx *), struct tty_ctx *);
+void	tty_write(void (*)(struct tty *, const struct tty_ctx *),
+	    struct tty_ctx *);
+int	tty_client_ready(struct client *, struct window_pane *wp);
 void	tty_cmd_alignmenttest(struct tty *, const struct tty_ctx *);
 void	tty_cmd_cell(struct tty *, const struct tty_ctx *);
 void	tty_cmd_clearendofline(struct tty *, const struct tty_ctx *);
diff --git a/tty.c b/tty.c
index a9f49c9b..a58ca937 100644
--- a/tty.c
+++ b/tty.c
@@ -723,9 +723,23 @@ tty_draw_line(struct tty *tty, const struct window_pane *wp,
 	tty_update_mode(tty, tty->mode, s);
 }
 
+int
+tty_client_ready(struct client *c, struct window_pane *wp)
+{
+	if (c->session == NULL || c->tty.term == NULL)
+		return (0);
+	if (c->flags & CLIENT_SUSPENDED)
+		return (0);
+	if (c->tty.flags & TTY_FREEZE)
+		return (0);
+	if (c->session->curw->window != wp->window)
+		return (0);
+	return (1);
+}
+
 void
-tty_write(
-    void (*cmdfn)(struct tty *, const struct tty_ctx *), struct tty_ctx *ctx)
+tty_write(void (*cmdfn)(struct tty *, const struct tty_ctx *),
+    struct tty_ctx *ctx)
 {
 	struct window_pane	*wp = ctx->wp;
 	struct client		*c;
@@ -740,13 +754,7 @@ tty_write(
 		return;
 
 	TAILQ_FOREACH(c, &clients, entry) {
-		if (c->session == NULL || c->tty.term == NULL)
-			continue;
-		if (c->flags & CLIENT_SUSPENDED)
-			continue;
-		if (c->tty.flags & TTY_FREEZE)
-			continue;
-		if (c->session->curw->window != wp->window)
+		if (!tty_client_ready(c, wp))
 			continue;
 
 		ctx->xoff = wp->xoff;
diff --git a/window.c b/window.c
index 7edfed42..bc17656d 100644
--- a/window.c
+++ b/window.c
@@ -58,6 +58,7 @@ u_int	next_window_pane_id;
 u_int	next_window_id;
 u_int	next_active_point;
 
+void	window_pane_timer_callback(int, short, void *);
 void	window_pane_read_callback(struct bufferevent *, void *);
 void	window_pane_error_callback(struct bufferevent *, short, void *);
 
@@ -740,6 +741,9 @@ window_pane_destroy(struct window_pane *wp)
 {
 	window_pane_reset_mode(wp);
 
+	if (event_initialized(&wp->timer))
+		evtimer_del(&wp->timer);
+
 	if (wp->fd != -1) {
 		bufferevent_free(wp->event);
 		close(wp->fd);
@@ -867,28 +871,53 @@ window_pane_spawn(struct window_pane *wp, int argc, char **argv,
 
 	wp->event = bufferevent_new(wp->fd, window_pane_read_callback, NULL,
 	    window_pane_error_callback, wp);
+
+	bufferevent_setwatermark(wp->event, EV_READ, 0, READ_SIZE);
 	bufferevent_enable(wp->event, EV_READ|EV_WRITE);
 
 	free(cmd);
 	return (0);
 }
 
+void
+window_pane_timer_callback(unused int fd, unused short events, void *data)
+{
+	window_pane_read_callback(NULL, data);
+}
+
 void
 window_pane_read_callback(unused struct bufferevent *bufev, void *data)
 {
-	struct window_pane     *wp = data;
-	char   		       *new_data;
-	size_t			new_size;
+	struct window_pane	*wp = data;
+	struct evbuffer		*evb = wp->event->input;
+	char			*new_data;
+	size_t			 new_size, available;
+	struct client		*c;
+	struct timeval		 tv;
 
-	new_size = EVBUFFER_LENGTH(wp->event->input) - wp->pipe_off;
+	if (event_initialized(&wp->timer))
+		evtimer_del(&wp->timer);
+
+	log_debug("%%%u has %zu bytes", wp->id, EVBUFFER_LENGTH(evb));
+
+	TAILQ_FOREACH(c, &clients, entry) {
+		if (!tty_client_ready(c, wp))
+			continue;
+
+		available = EVBUFFER_LENGTH(c->tty.event->output);
+		if (available > READ_BACKOFF)
+			goto start_timer;
+	}
+
+	new_size = EVBUFFER_LENGTH(evb) - wp->pipe_off;
 	if (wp->pipe_fd != -1 && new_size > 0) {
-		new_data = EVBUFFER_DATA(wp->event->input);
+		new_data = EVBUFFER_DATA(evb);
 		bufferevent_write(wp->pipe_event, new_data, new_size);
 	}
 
 	input_parse(wp);
 
-	wp->pipe_off = EVBUFFER_LENGTH(wp->event->input);
+	wp->pipe_off = EVBUFFER_LENGTH(evb);
 
 	/*
 	 * If we get here, we're not outputting anymore, so set the silence
@@ -897,11 +926,22 @@ window_pane_read_callback(unused struct bufferevent *bufev, void *data)
 	wp->window->flags |= WINDOW_SILENCE;
 	if (gettimeofday(&wp->window->silence_timer, NULL) != 0)
 		fatal("gettimeofday failed.");
+	return;
+
+start_timer:
+	log_debug("%%%u backing off (%s %zu > %d)", wp->id, c->ttyname,
+	    available, READ_BACKOFF);
+
+	tv.tv_sec = 0;
+	tv.tv_usec = READ_TIME;
+
+	evtimer_set(&wp->timer, window_pane_timer_callback, wp);
+	evtimer_add(&wp->timer, &tv);
 }
 
 void
-window_pane_error_callback(
-    unused struct bufferevent *bufev, unused short what, void *data)
+window_pane_error_callback(unused struct bufferevent *bufev, unused short what,
+    void *data)
 {
 	struct window_pane *wp = data;