On Wed, 30 Aug 2017 22:18:13 -0700 Roopa Prabhu <roopa@xxxxxxxxxxxxxxxxxxx> wrote: > From: Roopa Prabhu <roopa@xxxxxxxxxxxxxxxxxxx> > > This extends bridge fdb table tracepoints to also cover > learned fdb entries in the br_fdb_update path. Note that > unlike other tracepoints I have moved this to when the fdb > is modified because this is in the datapath and can generate > a lot of noise in the trace output. br_fdb_update is also called > from added_by_user context in the NTF_USE case which is already > traced ..hence the !added_by_user check. > > Signed-off-by: Roopa Prabhu <roopa@xxxxxxxxxxxxxxxxxxx> > --- > include/trace/events/bridge.h | 31 +++++++++++++++++++++++++++++++ > net/bridge/br_fdb.c | 5 ++++- > net/core/net-traces.c | 1 + > 3 files changed, 36 insertions(+), 1 deletion(-) > > diff --git a/include/trace/events/bridge.h b/include/trace/events/bridge.h > index 0f1cde0..1bee3e7 100644 > --- a/include/trace/events/bridge.h > +++ b/include/trace/events/bridge.h > @@ -92,6 +92,37 @@ TRACE_EVENT(fdb_delete, > __entry->addr[4], __entry->addr[5], __entry->vid) > ); > > +TRACE_EVENT(br_fdb_update, > + > + TP_PROTO(struct net_bridge *br, struct net_bridge_port *source, > + const unsigned char *addr, u16 vid, bool added_by_user), > + > + TP_ARGS(br, source, addr, vid, added_by_user), > + > + TP_STRUCT__entry( > + __string(br_dev, br->dev->name) > + __string(dev, source->dev->name) I have found that using the device string name is (1) slow as it involves strcpy+strlen See [1]+[2] where a single dev-name costed me 16 ns, and the base overhead of a bpf attached tracepoint is 25 ns (see [3]). [1] https://git.kernel.org/davem/net-next/c/e7d12ce121a [2] https://git.kernel.org/davem/net-next/c/315ec3990ef [3] https://git.kernel.org/davem/net-next/c/25d4dae1a64 (2) strings are also harder to work-with/extract when attaching a bpf_prog See the trouble I'm in accessing a dev string here napi:napi_poll here: https://github.com/netoptimizer/prototype-kernel/blob/103b955a080/kernel/samples/bpf/napi_monitor_kern.c#L52-L58 Using ifindex'es in userspace is fairly easy see man if_indextoname(3). > + __array(unsigned char, addr, ETH_ALEN) > + __field(u16, vid) > + __field(bool, added_by_user) > + ), > + > + TP_fast_assign( > + __assign_str(br_dev, br->dev->name); > + __assign_str(dev, source->dev->name); > + memcpy(__entry->addr, addr, ETH_ALEN); > + __entry->vid = vid; > + __entry->added_by_user = added_by_user; > + ), > + > + TP_printk("br_dev %s source %s addr %02x:%02x:%02x:%02x:%02x:%02x vid %u added_by_user %d", > + __get_str(br_dev), __get_str(dev), __entry->addr[0], > + __entry->addr[1], __entry->addr[2], __entry->addr[3], > + __entry->addr[4], __entry->addr[5], __entry->vid, > + __entry->added_by_user) > +); -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat LinkedIn: http://www.linkedin.com/in/brouer
