System Administration Commands syncstat(1M)
NAME
syncstat - 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 synchronous 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 dev-
ice driver, along with a number indicating the channel
number (ppa) under control of that driver.
Event statistics are maintained by a driver for each physi-
cal 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.
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System Administration Commands syncstat(1M)
OPTIONS
-c Clear the accumulated statistics for the device
specified. 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 average packet sizes. These
are the relationships between bytes transferred
and the baud rate, expressed as percentages. 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 gen-
erated 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%
ATRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
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System Administration Commands syncstat(1M)
ATRIBUTE TYPE ATRIBUTE VALUE
Availability SUNWcsu
SEE ALSO
syncinit(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 utilization 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 proto-
cols. However, because the overhead involved in recovering
from a link error can be much greater than that of normal
operation, 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 supporting 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 percentage of use
greatly exceeds 100%, or never exceeds 50%, then the baud
rate set for the device probably does not reflect the speed
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System Administration Commands syncstat(1M)
of the modem.
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