Documentation/networking/statistics.rst

4 Interface statistics
10 This document is a guide to Linux network interface statistics.
12 There are three main sources of interface statistics in Linux:
14  - standard interface statistics based on
16  - protocol-specific statistics; and
17  - driver-defined statistics available via ethtool.
19 Standard interface statistics
22 There are multiple interfaces to reach the standard statistics.
44 Protocol-specific statistics
47 Protocol-specific statistics are exposed via relevant interfaces,
53 Ethtool exposes common low-level statistics.
54 All the standard statistics are expected to be maintained
66 Standard ethtool statistics can be accessed via the interfaces used
70   $ ethtool --include-statistics -a eth0
75   Statistics:
79 General Ethernet statistics not associated with any particular
100 Driver-defined statistics
103 Driver-defined ethtool statistics can be dumped using `ethtool -S $ifc`, e.g.::
106   NIC statistics:
117 of interfaces as well as their statistics.
126 Each device directory in sysfs contains a `statistics` directory (e.g.
127 `/sys/class/net/lo/statistics/`) with files corresponding to
137 `Documentation/ABI/testing/sysfs-class-net-statistics`.
146 Statistics are reported both in the responses to link information
154 specific statistics. Historically it has also been used to report
155 statistics for which other APIs did not exist, like per-device-queue
156 statistics, or standard-based statistics (e.g. RFC 2863).
158 Statistics and their string identifiers are retrieved separately.
161 to retrieve the number of statistics (`.n_stats`).
168 Protocol-related statistics can be requested in get commands by setting
170 statistics are supported in the following commands:
179 Some drivers expose extra statistics via `debugfs`.
190 Drivers should report all statistics which have a matching member in
197 Please note for example that detailed error statistics must be
201 via `/proc/net/dev`. If driver may sleep when retrieving the statistics
204 allows setting the frequency of refreshing statistics, if needed.
206 Retrieving ethtool statistics is a multi-syscall process, drivers are advised
207 to keep the number of statistics constant to avoid race conditions with
210 Statistics must persist across routine operations like bringing the interface
218 the statistics they don't report with 0.