Commit 8c00bd93 authored by Jakub Kicinski's avatar Jakub Kicinski Committed by David S. Miller
Browse files

docs: net: include the new ethtool pause stats in the stats doc 



Tell people that there now is an interface for querying pause frames.
A little bit of restructuring is needed given this is a first source
of such statistics.

Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
Reviewed-by: default avatarSaeed Mahameed <saeedm@nvidia.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 9a27a330

Documentation/networking/statistics.rst

+52 −5
Original line number Diff line number Diff line
@@ -4,16 +4,23 @@ 
Interface statistics

====================



Overview

========



This document is a guide to Linux network interface statistics.



There are two main sources of interface statistics in Linux:

There are three main sources of interface statistics in Linux:



 - standard interface statistics based on

   :c:type:`struct rtnl_link_stats64 <rtnl_link_stats64>`; and

   :c:type:`struct rtnl_link_stats64 <rtnl_link_stats64>`;

 - protocol-specific statistics; and

 - driver-defined statistics available via ethtool.



There are multiple interfaces to reach the former. Most commonly used

is the `ip` command from `iproute2`::

Standard interface statistics

-----------------------------



There are multiple interfaces to reach the standard statistics.

Most commonly used is the `ip` command from `iproute2`::



  $ ip -s -s link show dev ens4u1u1

  6: ens4u1u1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP mode DEFAULT group default qlen 1000
@@ -34,7 +41,26 @@ If `-s` is specified once the detailed errors won't be shown. 


`ip` supports JSON formatting via the `-j` option.



Ethtool statistics can be dumped using `ethtool -S $ifc`, e.g.::

Protocol-specific statistics

----------------------------



Some of the interfaces used for configuring devices are also able

to report related statistics. For example ethtool interface used

to configure pause frames can report corresponding hardware counters::



  $ ethtool --include-statistics -a eth0

  Pause parameters for eth0:

  Autonegotiate:	on

  RX:			on

  TX:			on

  Statistics:

    tx_pause_frames: 1

    rx_pause_frames: 1



Driver-defined statistics

-------------------------



Driver-defined ethtool statistics can be dumped using `ethtool -S $ifc`, e.g.::



  $ ethtool -S ens4u1u1

  NIC statistics:
@@ -94,6 +120,17 @@ Identifiers via `ETHTOOL_GSTRINGS` with `string_set` set to `ETH_SS_STATS`, 
and values via `ETHTOOL_GSTATS`. User space should use `ETHTOOL_GDRVINFO`

to retrieve the number of statistics (`.n_stats`).



ethtool-netlink

---------------



Ethtool netlink is a replacement for the older IOCTL interface.



Protocol-related statistics can be requested in get commands by setting

the `ETHTOOL_FLAG_STATS` flag in `ETHTOOL_A_HEADER_FLAGS`. Currently

statistics are supported in the following commands:



  - `ETHTOOL_MSG_PAUSE_GET`



debugfs

-------
@@ -130,3 +167,13 @@ user space trying to read them. 


Statistics must persist across routine operations like bringing the interface

down and up.



Kernel-internal data structures

-------------------------------



The following structures are internal to the kernel, their members are

translated to netlink attributes when dumped. Drivers must not overwrite

the statistics they don't report with 0.



.. kernel-doc:: include/linux/ethtool.h

    :identifiers: ethtool_pause_stats