xbstat - monitor Crossbow (Xbow) traffic
xbstat [-d devname] [-t sec]
xbstat monitors the traffic from and to each of the active slots of the
Crossbow (Xbow) i/o interconnect. It reports the total number of
micropackets sent from and received at each link. It also reports the
LLP retries at each link.
The -d devname option specifies which Crossbow to monitor in a multiCrossbow
system. devname should be a valid Xtalk monitor point under the
/hw graph. If the devname is not explicitly specified, xbstat monitors
/dev/xbmon by default.
The -t sec option determines the duration of time in units of seconds
that the Xbow traffic will be monitored. If this option is not is
selected, the monitoring continues until the user terminates it with a
CTRL-C (or intr).
xbstat gets its information from the two hardware performance counters
and the Link Auxiliary Status Registers in the Xbow. It uses a
multiplexing technique to sample and report the SRC and DST link traffic
at each XBow slot. Cumulative counts since the beginning of the
monitoring period are reported in units of micropackets.
xbstat is capable of monitoring any selected Xbow in a multi-Xbow system.
Use find /hw -name mon -print | grep xtalk to find all possible Xbow
monitor points. A specific Xbow can be selected in two ways: explicitly,
as a devname with the -d option, or implicitly, as a soft link to
When specifying the Xbow implicitly, first create a symbolic link between
the selected Xbow monitor point and /dev/xbmon before invoking this
command. See examples below.
Multiple instances of the command selecting different Xbows can be
executed at a time. However, one Xbow can be specified at a time with
each instance of the command.
The monitor data is statistical since the traffic over many links and
slots is sampled or scanned during any given monitoring period. All live
links are monitored for the same amount of time during any monitoring
Note that each slot consists of two links: SRC (Source) and
Slot Physical slot being monitored. I/O slots will be labeled
as IO1 through IO12, node slots will have labels N1 through
N4. Devices connected to each slot vary and are platform
and configuration dependent.
Flags Selected flags from the Link(x) Auxiliary Status register.
Currently only the "Widget Present" flag is shown to
indicate an active/live slot.
Source Number of micropackets sent from the SRC link of this slot.
Destination Number of micropackets received at the DST link of this
RcRtry Number of LLP receive retries.
TxRtry Number of LLP transmit retries.
xbstat -d /hw/module/1/slot/n1/node/xtalk/0/mon -t 60
Monitors for 60 seconds the traffic at the Xbow specified.
ln -s /hw/node/xtalk/0/mon /dev/xbmon;
xbstat -t 60
Monitors for 60 seconds the traffic at the Xbow associated with
Monitors traffic until terminated by CTRL-C at the Xbow associated with
The command requires root privilege to run.
When a Xbow is not explicitly specified, make sure that /dev/xbmon points
to an existing Xbow in the system.
linkstat(1), nstats(1), sn(1), hwgraph(4).
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