syncstat(1M) System Administration Commands syncstat(1M)NAMEsyncstat - report driver statistics from a synchronous serial link
SYNOPSIS
/usr/sbin/syncstat [-c] device [interval]
DESCRIPTION
The syncstat command reports the event statistics maintained by a syn‐
chronous serial device driver. The report may be a single snapshot of
the accumulated totals, or a series of samples showing incremental
changes. Prior to these it prints the device name being used to query a
particular device driver, along with a number indicating the channel
number (ppa) under control of that driver.
Event statistics are maintained by a driver for each physical channel
that it supports. They are initialized to zero at the time the driver
module is loaded into the system, which may be either at boot time or
when one of the driver's entry points is first called.
The device argument is the name of the serial device as it appears in
the /dev directory. For example, zsh0 specifies the first on-board
serial device.
The following is a breakdown of syncstat output:
speed The line speed the device has been set to
operate at. It is the user's responsibility
to make this value correspond to the modem
clocking speed when clocking is provided by
the modem.
ipkts The total number of input packets.
opkts The total number of output packets.
undrun The number of transmitter underrun errors.
ovrrun The number of receiver overrun errors.
abort The number of aborted received frames.
crc The number of received frames with CRC
errors.
isize The average size (in bytes) of input pack‐
ets.
osize The average size (in bytes) of output pack‐
ets.
OPTIONS-c Clear the accumulated statistics for the device speci‐
fied. This may be useful when it is not desirable to
unload a particular driver, or when the driver is not
capable of being unloaded.
interval syncstat samples the statistics every interval seconds
and reports incremental changes. The output reports
line utilization for input and output in place of aver‐
age packet sizes. These are the relationships between
bytes transferred and the baud rate, expressed as per‐
centages. The loop repeats indefinitely, with a column
heading printed every twenty lines for convenience.
EXAMPLES
Example 1: Sample output from the syncstat command:
example# syncstat zsh0
speed ipkts opkts undrun ovrrun abort crc isize osize
9600 15716 17121 0 0 1 3 98 89
example# syncstat-c zsh0
speed ipkts opkts undrun ovrrun abort crc isize osize
9600 0 0 0 0 0 0 0 0
In the following sample output a new line of output is generated every
five seconds:
example# syncstat zsh0 5
ipkts opkts undrun ovrrun abort crc iutil outil
12 10 0 0 0 0 5% 4%
22 60 0 0 0 0 3% 90%
36 14 0 0 0 1 51% 2%
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│Availability │SUNWcsu │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOsyncinit(1M), syncloop(1M), attributes(5), zsh(7D)DIAGNOSTICS
bad interval: arg The argument arg is expected
to be an interval and could not
be understood.
device missing minor device number The name device does not end
in a decimal number that can be
used as a minor device number.
baud rate not set The interval option is being
used and the baud rate on the
device is zero. This would
cause a divide-by-zero error
when computing the line uti‐
lization statistics.
WARNINGS
Underrun, overrun, frame-abort, and CRC errors have a variety of
causes. Communication protocols are typically able to handle such
errors and initiate recovery of the transmission in which the error
occurred. Small numbers of such errors are not a significant problem
for most protocols. However, because the overhead involved in recover‐
ing from a link error can be much greater than that of normal opera‐
tion, high error rates can greatly degrade overall link throughput.
High error rates are often caused by problems in the link hardware,
such as cables, connectors, interface electronics or telephone lines.
They may also be related to excessive load on the link or the support‐
ing system.
The percentages for input and output line utilization reported when
using the interval option may occasionally be reported as slightly
greater than 100% because of inexact sampling times and differences in
the accuracy between the system clock and the modem clock. If the per‐
centage of use greatly exceeds 100%, or never exceeds 50%, then the
baud rate set for the device probably does not reflect the speed of the
modem.
SunOS 5.10 9 Mar 1993 syncstat(1M)
