docs: networking: extend the statistics documentation

Make the lack of expectations for switching NICs explicit,
describe the new stats.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jakub Kicinski 2021-04-16 12:27:37 -07:00 committed by David S. Miller
parent e5272ad4aa
commit f117c48c0d
1 changed files with 42 additions and 2 deletions

View File

@ -44,8 +44,27 @@ If `-s` is specified once the detailed errors won't be shown.
Protocol-specific statistics
----------------------------
Some of the interfaces used for configuring devices are also able
to report related statistics. For example ethtool interface used
Protocol-specific statistics are exposed via relevant interfaces,
the same interfaces as are used to configure them.
ethtool
~~~~~~~
Ethtool exposes common low-level statistics.
All the standard statistics are expected to be maintained
by the device, not the driver (as opposed to driver-defined stats
described in the next section which mix software and hardware stats).
For devices which contain unmanaged
switches (e.g. legacy SR-IOV or multi-host NICs) the events counted
may not pertain exclusively to the packets destined to
the local host interface. In other words the events may
be counted at the network port (MAC/PHY blocks) without separation
for different host side (PCIe) devices. Such ambiguity must not
be present when internal switch is managed by Linux (so called
switchdev mode for NICs).
Standard ethtool statistics can be accessed via the interfaces used
for configuration. For example ethtool interface used
to configure pause frames can report corresponding hardware counters::
$ ethtool --include-statistics -a eth0
@ -57,6 +76,27 @@ to configure pause frames can report corresponding hardware counters::
tx_pause_frames: 1
rx_pause_frames: 1
General Ethernet statistics not associated with any particular
functionality are exposed via ``ethtool -S $ifc`` by specifying
the ``--groups`` parameter::
$ ethtool -S eth0 --groups eth-phy eth-mac eth-ctrl rmon
Stats for eth0:
eth-phy-SymbolErrorDuringCarrier: 0
eth-mac-FramesTransmittedOK: 1
eth-mac-FrameTooLongErrors: 1
eth-ctrl-MACControlFramesTransmitted: 1
eth-ctrl-MACControlFramesReceived: 0
eth-ctrl-UnsupportedOpcodesReceived: 1
rmon-etherStatsUndersizePkts: 1
rmon-etherStatsJabbers: 0
rmon-rx-etherStatsPkts64Octets: 1
rmon-rx-etherStatsPkts65to127Octets: 0
rmon-rx-etherStatsPkts128to255Octets: 0
rmon-tx-etherStatsPkts64Octets: 2
rmon-tx-etherStatsPkts65to127Octets: 3
rmon-tx-etherStatsPkts128to255Octets: 0
Driver-defined statistics
-------------------------