man: Add man pages for the "stats" functions

Add a man page for the new "stats" command.
Also mention the new "stats" group in ip-monitor.

Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: David Ahern <dsahern@kernel.org>

3 files changed, 167 insertions, 2 deletions

diff --git a/man/man8/ip-monitor.8 b/man/man8/ip-monitor.8
index f886d31b8..ec033c691 100644
--- a/man/man8/ip-monitor.8
+++ b/man/man8/ip-monitor.8
@@ -55,7 +55,7 @@ command is the first in the command line and then the object list follows:
 is the list of object types that we want to monitor.
 It may contain
 .BR link ", " address ", " route ", " mroute ", " prefix ", "
-.BR neigh ", " netconf ", "  rule ", " nsid " and " nexthop "."
+.BR neigh ", " netconf ", "  rule ", " stats ", " nsid " and " nexthop "."
 If no
 .B file
 argument is given,
diff --git a/man/man8/ip-stats.8 b/man/man8/ip-stats.8
new file mode 100644
index 000000000..7eaaf122b
--- /dev/null
+++ b/man/man8/ip-stats.8
@@ -0,0 +1,160 @@
+.TH IP\-STATS 8 "16 Mar 2022" "iproute2" "Linux"
+.SH NAME
+ip-stats \- manage and show interface statistics
+.SH SYNOPSIS
+.sp
+.ad l
+.in +8
+.ti -8
+.B ip
+.B stats
+.RI  " { " COMMAND " | "
+.BR help " }"
+.sp
+
+.ti -8
+.BR "ip stats show"
+.RB "[ " dev
+.IR DEV " ] "
+.RB "[ " group
+.IR GROUP " [ "
+.BI subgroup " SUBGROUP"
+.R " ] ... ] ..."
+
+.ti -8
+.BR "ip stats set"
+.BI dev " DEV"
+.BR l3_stats " { "
+.BR on " | " off " }"
+
+.SH DESCRIPTION
+
+.TP
+.B ip stats set
+is used for toggling whether a certain HW statistics suite is collected on
+a given netdevice. The following statistics suites are supported:
+
+.in 21
+
+.ti 14
+.B l3_stats
+L3 stats reflect traffic that takes place in a HW device on an object that
+corresponds to the given software netdevice.
+
+.TP
+.B ip stats show
+is used for showing stats on a given netdevice, or dumping statistics
+across all netdevices. By default, all stats are requested. It is possible
+to filter which stats are requested by using the
+.B group
+and
+.B subgroup
+keywords.
+
+It is possible to specify several groups, or several subgroups for one
+group. When no subgroups are given for a group, all the subgroups are
+requested.
+
+The following groups are recognized:
+.in 21
+
+.ti 14
+.B group link
+- Link statistics. The same suite that "ip -s link show" shows.
+
+.ti 14
+.B group offload
+- A group that contains a number of HW-oriented statistics. See below for
+individual subgroups within this group.
+
+.TQ
+.BR "group offload " subgroups:
+.in 21
+
+.ti 14
+.B subgroup cpu_hit
+- The
+.B cpu_hit
+statistics suite is useful on hardware netdevices. The
+.B link
+statistics on these devices reflect both the hardware- and
+software-datapath traffic. The
+.B cpu_hit
+statistics then only reflect software-datapath traffic.
+
+.ti 14
+.B subgroup hw_stats_info
+- This suite does not include traffic statistics, but rather communicates
+the state of other statistics. Through this subgroup, it is possible to
+discover whether a given statistic was enabled, and when it was, whether
+any device driver actually configured its device to collect these
+statistics. For example,
+.B l3_stats
+was enabled in the following case, but no driver has installed it:
+
+# ip stats show dev swp1 group offload subgroup hw_stats_info
+.br
+56: swp1: group offload subgroup hw_stats_info
+.br
+    l3_stats on used off
+
+After an L3 address is added to the netdevice, the counter will be
+installed:
+
+# ip addr add dev swp1 192.0.2.1/28
+.br
+# ip stats show dev swp1 group offload subgroup hw_stats_info
+.br
+56: swp1: group offload subgroup hw_stats_info
+.br
+    l3_stats on used on
+
+.ti 14
+.B subgroup l3_stats
+- These statistics reflect L3 traffic that takes place in HW on an object
+that corresponds to the netdevice. Note that this suite is disabled by
+default and needs to be first enabled through
+.B ip stats set\fR.
+
+For example:
+
+# ip stats show dev swp2.200 group offload subgroup l3_stats
+.br
+112: swp2.200: group offload subgroup l3_stats on used on
+.br
+    RX:  bytes packets errors dropped   mcast
+.br
+          8900      72      2       0       3
+.br
+    TX:  bytes packets errors dropped
+.br
+          7176      58      0       0
+
+Note how the l3_stats_info for the selected group is also part of the dump.
+
+.SH EXAMPLES
+.PP
+# ip stats set dev swp1 l3_stats on
+.RS
+Enables collection of L3 HW statistics on swp1.
+.RE
+
+.PP
+# ip stats show group offload
+.RS
+Shows all offload statistics on all netdevices.
+.RE
+
+.PP
+# ip stats show dev swp1 group link
+.RS
+Shows link statistics on the given netdevice.
+.RE
+
+.SH SEE ALSO
+.br
+.BR ip (8),
+.BR ip-link (8),
+
+.SH AUTHOR
+Manpage by Petr Machata.
diff --git a/man/man8/ip.8 b/man/man8/ip.8
index 2a4848b78..f6adbc772 100644
--- a/man/man8/ip.8
+++ b/man/man8/ip.8
@@ -22,7 +22,7 @@ ip \- show / manipulate routing, network devices, interfaces and tunnels
 .BR link " | " address " | " addrlabel " | " route " | " rule " | " neigh " | "\
  ntable " | " tunnel " | " tuntap " | " maddress " | "  mroute " | " mrule " | "\
  monitor " | " xfrm " | " netns " | "  l2tp " | "  tcp_metrics " | " token " | "\
- macsec " | " vrf " | " mptcp " | " ioam " }"
+ macsec " | " vrf " | " mptcp " | " ioam " | " stats " }"
 .sp
 
 .ti -8
@@ -303,6 +303,10 @@ readability.
 - rule in routing policy database.
 
 .TP
+.B stats
+- manage and show interface statistics.
+
+.TP
 .B tcp_metrics/tcpmetrics
 - manage TCP Metrics
 
@@ -419,6 +423,7 @@ was written by Alexey N. Kuznetsov and added in Linux 2.2.
 .BR ip-ntable (8),
 .BR ip-route (8),
 .BR ip-rule (8),
+.BR ip-stats (8)
 .BR ip-tcp_metrics (8),
 .BR ip-token (8),
 .BR ip-tunnel (8),