Date: Wed, 16 Nov 2005 14:06:05 -0800 (PST) From: Dirk-Willem van Gulik <dirkx@webweaving.org> To: freebsd-hackers@freebsd.org Subject: Dealing with silo overflow and interrupt-level buffer overflow in sio(4) Message-ID: <20051116140145.V22890@skutsje.san.webweaving.org> In-Reply-To: <Pine.OSX.4.61.0511161139150.3380@gprs133.anywi.koole.com> References: <Pine.OSX.4.61.0511161139150.3380@gprs133.anywi.koole.com>
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I found that for virtually all GPRS and UMTS cards I tried that I get so
many interopt and silo overflow errors as to virtually make the card
unusable.
Attached patch below allows one to increase the buffer a bit; relative to
the speed of the connection.
Thanks,
Dw.
*** sio.c.orig Wed Nov 16 21:49:23 2005
--- sio.c Wed Nov 16 21:57:46 2005
***************
*** 1906,1911 ****
--- 1907,1915 ----
return (0);
}
+
+ static int cp4tick_rate = 4;
+ TUNABLE_INT("machdep.sio.cp4tick_rate", &cp4tick_rate);
/*
* This function must be called with the sio_lock mutex released and will
* return with it obtained.
***************
*** 1926,1932 ****
* (about 3 ticks if input flow control is not used or not honoured,
* but a bit less for CS5-CS7 modes).
*/
! cp4ticks = 40 * speed / 10 / hz * 4;
for (ibufsize = 128; ibufsize < cp4ticks;)
ibufsize <<= 1;
if (ibufsize == com->ibufsize) {
--- 1930,1936 ----
* (about 3 ticks if input flow control is not used or not honoured,
* but a bit less for CS5-CS7 modes).
*/
! cp4ticks = (cp4tick_rate ? cp4tick_rate : 4) * speed / 10 / hz;
for (ibufsize = 128; ibufsize < cp4ticks;)
ibufsize <<= 1;
if (ibufsize == com->ibufsize) {root@builld-jv#
diff -c sio.4.orig
sio.4
*** sio.4.orig Wed Nov 16 21:57:33 2005
--- sio.4 Wed Nov 16 22:02:04 2005
***************
*** 363,368 ****
--- 363,381 ----
.Pp
The device numbers are made from the set [0-9a-v] so that more than
10 ports can be supported.
+ .Sh TUNABLES
+ The driver supports the following tunable parameters, which may be
+ added to
+ .Pa /boot/loader.conf
+ or set via the
+ .Xr sysctl 8
+ command:
+ .Bl -tag -width ".Cm machdep.sio.cp4tick_rate " -compact
+ .It Cm machdep.sio.cp4tick_rate
+ Rate by which to increase the buffer ti handle softtty interrupt
+ latency. Default value is 4; to deal with about 2-3 ticks without
+ loss of throughput or data.
+ .El
.Sh DIAGNOSTICS
.Bl -diag
.It sio%d: silo overflow.
***************
*** 370,382 ****
.El
.Bl -diag
.It sio%d: interrupt-level buffer overflow.
! Problem in the bottom half of the driver.
.El
.Bl -diag
.It sio%d: tty-level buffer overflow.
Problem in the application.
Input has arrived faster than the given module could process it
! and some has been lost.
.El
.\" .Bl -diag
.\" .It sio%d: reduced fifo trigger level to %d.
--- 383,395 ----
.El
.Bl -diag
.It sio%d: interrupt-level buffer overflow.
! Problem in the bottom half of the driver. Try increasing
machdep.sio.cp4tick_rate.
.El
.Bl -diag
.It sio%d: tty-level buffer overflow.
Problem in the application.
Input has arrived faster than the given module could process it
! and some has been lost. Try increasing machdep.sio.cp4tick_rate.
.El
.\" .Bl -diag
.\" .It sio%d: reduced fifo trigger level to %d.
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