Hi Christian, On Fri, 23 Aug 2019 at 11:21, Christian Leeb <christian.l...@ch.abb.com> wrote: > > Hi > > > > We are using 802.1Q tag for PTP. Fine with setting VLAN ID. > > How can I set PCP (priority code point in 802.1Q tag) specifically for PTP? > > This is how far I got: > > By default, applications are using skb (Linux socket buffer) priority 0. > skb priority can be statically mapped to PCP using vconfig set_egress_map. > E.g. “vconfig set_egress_map eth0.100 0 7” maps all skb prio 0 to PCP 7. This > for eth0.100. > > > > Is it possible to set skb prio used by ptp4l? > >
Linuxptp master supports the SO_PRIORITY API since this commit: https://github.com/richardcochran/linuxptp/commit/c15e8c76000cdd00335a039f89693b820044ac91 Prior to that, you needed to do skbedit trickery. Here is an example on how to match L2 PTP by EtherType: # Add the qdisc holding the classifiers $ tc qdisc add dev "${iface}" clsact # Match L2 PTP frames by EtherType # Since we use u32 filter which starts from IP protocol, # we need to go back and specify -2 negative offset. $ tc filter add dev "${iface}" egress prio 1 u32 match u16 0x88f7 0xffff at -2 action skbedit priority 7 I suppose it's possible to get a similar effect using the netfilter mangle table and -j CLASSIFY --set-class 0:7, but I'm not exactly sure how to match on PTP using that one. By the way you might also need a qdisc that maps skb->priority to netdev queue, like mqprio. > > In practice we would like to map per application, e.g. PCP = 7 for PTP, PCP = > 5 for “application 1”. Current PTP4L does not support this, so it sends with > skb prio = 0 (the default). As a workaround we could map skb prio 0 to target > PCP and set skb prio of all other applications values other than 0. > > > > Regards, Chris > > _______________________________________________ > Linuxptp-users mailing list > Linuxptp-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/linuxptp-users Hope this helps, -Vladimir _______________________________________________ Linuxptp-users mailing list Linuxptp-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linuxptp-users
