On Fri, 10 Nov 2017 14:34:36 -0800 Jesus Sanchez-Palencia <jesus.sanchez-palen...@intel.com> wrote:
> In order to calculate the idleSlope parameter of CBS correctly, users > must take into account the entire packet size, including the overhead > from all layers. > > Add some more details to the man page to clarify that, giving one > simple example and pointing users to the correct 802.1Q section for > further clarifications if needed. > > Signed-off-by: Jesus Sanchez-Palencia <jesus.sanchez-palen...@intel.com> > --- > man/man8/tc-cbs.8 | 14 +++++++++++++- > 1 file changed, 13 insertions(+), 1 deletion(-) > > diff --git a/man/man8/tc-cbs.8 b/man/man8/tc-cbs.8 > index 97e00c84..32e1e0d4 100644 > --- a/man/man8/tc-cbs.8 > +++ b/man/man8/tc-cbs.8 > @@ -43,7 +43,19 @@ second) when there is at least one packet waiting for > transmission. > Packets are transmitted when the current value of credits is equal or > greater than zero. When there is no packet to be transmitted the > amount of credits is set to zero. This is the main tunable of the CBS > -algorithm. > +algorithm and represents the bandwidth that will be consumed. > +Note that when calculating idleslope, the entire packet size must be > +considered, including headers from all layers (i.e. MAC framing and any > +overhead from the physical layer), as described by IEEE 802.1Q-2014 > +section 34.4. > + > +As an example, for an ethernet frame carrying 284 bytes of payload, > +and with no VLAN tags, you must add 14 bytes for the Ethernet headers, > +4 bytes for the Frame check sequence (CRC), and 20 bytes for the L1 > +overhead: 12 bytes of interpacket gap, 7 bytes of preamble and 1 byte > +of start of frame delimiter. That results in 322 bytes for the total > +packet size, which is then used for calculating the idleslope. > + > .TP > sendslope > Sendslope is the rate of credits that is depleted (it should be a Applied to net-next
