Hi,
the buffer sizes allocated in the tty layer are too small for todays use
cases like l2tp and virtio-console. Also, the watermarks used by ppp are
way to small and do not scale with the line speed.
This patch
- makes 115200 the default speed for buffer sizing in ttymalloc(). A lot
of devices call ttymalloc(0) so this affects quite a few of them.
- increases the buffer size for 9600 < baud <= 115200 from 1k to 4k
- makes ppp use the lo/hi watermarks from the tty layer which are adjusted
according to speed + buffer size. The previous fixed values of 100 and 400
were way too small
- make pty call ttymalloc with baud == 1000000, which is the common value
used in the tree for "fast".
A slightly different variant of these changes were suggested and tested by
Sergey Ryazanov. They result in significant speed-up when sending data
with l2tp. I have also seen similar speed-up with the viocon driver.
I am looking for OKs, comments, additional testers (especially normal ppp
(not l2tp)).
Cheers,
Stefan
diff --git sys/kern/tty.c sys/kern/tty.c
index b276061..c9230be 100644
--- sys/kern/tty.c
+++ sys/kern/tty.c
@@ -2330,8 +2330,13 @@ ttymalloc(int baud)
tp = malloc(sizeof(struct tty), M_TTYS, M_WAITOK|M_ZERO);
- if (baud <= 115200)
+ if (baud == 0)
+ baud = 115200;
+
+ if (baud <= 9600)
tp->t_qlen = 1024;
+ else if (baud <= 115200)
+ tp->t_qlen = 4096;
else
tp->t_qlen = 8192;
clalloc(&tp->t_rawq, tp->t_qlen, 1);
diff --git sys/kern/tty_pty.c sys/kern/tty_pty.c
index 40b2db2..de009b8 100644
--- sys/kern/tty_pty.c
+++ sys/kern/tty_pty.c
@@ -193,7 +193,7 @@ check_pty(int minor)
if (!pt_softc[minor]) {
pti = malloc(sizeof(struct pt_softc), M_DEVBUF,
M_WAITOK|M_ZERO);
- pti->pt_tty = ttymalloc(0);
+ pti->pt_tty = ttymalloc(1000000);
ptydevname(minor, pti);
pt_softc[minor] = pti;
}
@@ -235,7 +235,7 @@ ptsopen(dev_t dev, int flag, int devtype, struct proc *p)
pti = pt_softc[minor(dev)];
if (!pti->pt_tty) {
- tp = pti->pt_tty = ttymalloc(0);
+ tp = pti->pt_tty = ttymalloc(1000000);
} else
tp = pti->pt_tty;
if ((tp->t_state & TS_ISOPEN) == 0) {
@@ -245,7 +245,7 @@ ptsopen(dev_t dev, int flag, int devtype, struct proc *p)
tp->t_oflag = TTYDEF_OFLAG;
tp->t_lflag = TTYDEF_LFLAG;
tp->t_cflag = TTYDEF_CFLAG;
- tp->t_ispeed = tp->t_ospeed = TTYDEF_SPEED;
+ tp->t_ispeed = tp->t_ospeed = 1000000;
ttsetwater(tp); /* would be done in xxparam() */
} else if (tp->t_state&TS_XCLUDE && suser(p, 0) != 0)
return (EBUSY);
@@ -412,7 +412,7 @@ ptcopen(dev_t dev, int flag, int devtype, struct proc *p)
pti = pt_softc[minor(dev)];
if (!pti->pt_tty) {
- tp = pti->pt_tty = ttymalloc(0);
+ tp = pti->pt_tty = ttymalloc(1000000);
} else
tp = pti->pt_tty;
if (tp->t_oproc)
diff --git sys/net/ppp_tty.c sys/net/ppp_tty.c
index 186d4c7..94d9d4e 100644
--- sys/net/ppp_tty.c
+++ sys/net/ppp_tty.c
@@ -155,9 +155,6 @@ struct pool ppp_pkts;
/* This is a NetBSD-1.0 or later kernel. */
#define CCOUNT(q) ((q)->c_cc)
-#define PPP_LOWAT 100 /* Process more output when < LOWAT on queue */
-#define PPP_HIWAT 400 /* Don't start a new packet if HIWAT on
queue */
-
/*
* Line specific open routine for async tty devices.
* Attach the given tty to the first available ppp unit.
@@ -499,7 +496,7 @@ pppasyncstart(struct ppp_softc *sc)
int s;
idle = 0;
- while (CCOUNT(&tp->t_outq) < PPP_HIWAT) {
+ while (CCOUNT(&tp->t_outq) < tp->t_hiwat) {
/*
* See if we have an existing packet partly sent.
* If not, get a new packet and start sending it.
@@ -706,7 +703,7 @@ pppstart_internal(struct tty *tp, int force)
* or been disconnected from the ppp unit, then tell if_ppp.c that
* we need more output.
*/
- if ((CCOUNT(&tp->t_outq) < PPP_LOWAT || force)
+ if ((CCOUNT(&tp->t_outq) < tp->t_lowat || force)
&& !((tp->t_state & TS_CARR_ON) == 0 && (tp->t_cflag & CLOCAL) == 0)
&& sc != NULL && tp == (struct tty *) sc->sc_devp) {
ppp_restart(sc);
