.TH DCB-PFC 8 "31 October 2020" "iproute2" "Linux"
.SH NAME
dcb-pfc \- show / manipulate PFC (Priority-based Flow Control) settings of
the DCB (Data Center Bridging) subsystem
.SH SYNOPSIS
.sp
.ad l
.in +8

.ti -8
.B dcb
.RI "[ " OPTIONS " ] "
.B pfc
.RI "{ " COMMAND " | " help " }"
.sp

.ti -8
.B dcb pfc show dev
.RI DEV
.RB "[ " pfc-cap " ]"
.RB "[ " prio-pfc " ]"
.RB "[ " macsec-bypass " ]"
.RB "[ " delay " ]"
.RB "[ " requests " ]"
.RB "[ " indications " ]"

.ti -8
.B dcb pfc set dev
.RI DEV
.RB "[ " prio-pfc " " \fIPFC-MAP " ]"
.RB "[ " macsec-bypass " { " on " | " off " } ]"
.RB "[ " delay " " \fIINTEGER\fR " ]"

.ti -8
.IR PFC-MAP " := [ " PFC-MAP " ] " PFC-MAPPING

.ti -8
.IR PFC-MAPPING " := { " PRIO " | " \fBall " }" \fB:\fR "{ "
.IR \fBon\fR " | " \fBoff\fR " }"

.ti -8
.IR PRIO " := { " \fB0\fR " .. " \fB7\fR " }"

.SH DESCRIPTION

.B dcb pfc
is used to configure Priority-based Flow Control attributes through Linux
DCB (Data Center Bridging) interface. PFC permits marking flows with a
certain priority as lossless, and holds related configuration, as well as
PFC counters.

.SH PARAMETERS

For read-write parameters, the following describes only the write direction,
i.e. as used with the \fBset\fR command. For the \fBshow\fR command, the
parameter name is to be used as a simple keyword without further arguments. This
instructs the tool to show the value of a given parameter. When no parameters
are given, the tool shows the complete PFC configuration.

.TP
.B pfc-cap
A read-only property that shows the number of traffic classes that may
simultaneously support PFC.

.TP
.B requests
A read-only count of the sent PFC frames per traffic class. Only shown when
-s is given, or when requested explicitly.

.TP
.B indications
A read-only count of the received PFC frames per traffic class. Only shown
when -s is given, or when requested explicitly.

.TP
.B macsec-bypass \fR{ \fBon\fR | \fBoff\fR }
Whether the sending station is capable of bypassing MACsec processing when
MACsec is disabled.

.TP
.B prio-pfc \fIPFC-MAP
\fIPFC-MAP\fR uses the array parameter syntax, see
.BR dcb (8)
for details. Keys are priorities, values are on / off indicators of whether
PFC is enabled for a given priority.

.TP
.B delay \fIINTEGER
The allowance made for round-trip propagation delay of the link in bits.
The value shall be 0..65535.

.SH EXAMPLE & USAGE

Enable PFC on priorities 6 and 7, leaving the rest intact:

.P
# dcb pfc set dev eth0 prio-pfc 6:on 7:on

Disable PFC of all priorities except 6 and 7, and configure delay to 4096
bits:

.P
# dcb pfc set dev eth0 prio-pfc all:off 6:on 7:on delay 0x1000

Show what was set:

.P
# dcb pfc show dev eth0
.br
pfc-cap 8 macsec-bypass off delay 4096
.br
prio-pfc 0:off 1:off 2:off 3:off 4:off 5:off 6:on 7:on

.SH EXIT STATUS
Exit status is 0 if command was successful or a positive integer upon failure.

.SH SEE ALSO
.BR dcb (8)

.SH REPORTING BUGS
Report any bugs to the Network Developers mailing list
.B <netdev@vger.kernel.org>
where the development and maintenance is primarily done.
You do not have to be subscribed to the list to send a message there.

.SH AUTHOR
Petr Machata <me@pmachata.org>