Re: Slowness forming TIPC cluster with explicit node addresses

[Chris Packham]

On Mon, 2019-07-29 at 09:04 +1200, Chris Packham wrote:
> On Fri, 2019-07-26 at 13:31 +0000, Jon Maloy wrote:
> > 
> > 
> > > 
> > > 
> > > -----Original Message-----
> > > From: netdev-owner@xxxxxxxxxxxxxxx <netdev-owner@xxxxxxxxxxxxxxx>
> > > On
> > > Behalf Of Chris Packham
> > > Sent: 25-Jul-19 19:37
> > > To: tipc-discussion@xxxxxxxxxxxxxxxxxxxxx
> > > Cc: netdev@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> > > Subject: Slowness forming TIPC cluster with explicit node
> > > addresses
> > > 
> > > Hi,
> > > 
> > > I'm having problems forming a TIPC cluster between 2 nodes.
> > > 
> > > This is the basic steps I'm going through on each node.
> > > 
> > > modprobe tipc
> > > ip link set eth2 up
> > > tipc node set addr 1.1.5 # or 1.1.6
> > > tipc bearer enable media eth dev eth0
> > eth2, I assume...
> > 
> Yes sorry I keep switching between between Ethernet ports for testing
> so I hand edited the email.
> 
> > 
> > > 
> > > 
> > > 
> > > Then to confirm if the cluster is formed I useÂtipc link list
> > > 
> > > [root@node-5 ~]# tipc link list
> > > broadcast-link: up
> > > ...
> > > 
> > > Looking at tcpdump the two nodes are sending packets
> > > 
> > > 22:30:05.782320 TIPC v2.0 1.1.5 > 0.0.0, headerlength 60 bytes,
> > > MessageSize
> > > 76 bytes, Neighbor Detection Protocol internal, messageType Link
> > > request
> > > 22:30:05.863555 TIPC v2.0 1.1.6 > 0.0.0, headerlength 60 bytes,
> > > MessageSize
> > > 76 bytes, Neighbor Detection Protocol internal, messageType Link
> > > request
> > > 
> > > Eventually (after a few minutes) the link does come up
> > > 
> > > [root@node-6Â~]# tipc link list
> > > broadcast-link: up
> > > 1001006:eth2-1001005:eth2: up
> > > 
> > > [root@node-5Â~]# tipc link list
> > > broadcast-link: up
> > > 1001005:eth2-1001006:eth2: up
> > > 
> > > When I remove the "tipc node set addr" things seem to kick into
> > > life straight
> > > away
> > > 
> > > [root@node-5 ~]# tipc link list
> > > broadcast-link: up
> > > 0050b61bd2aa:eth2-0050b61e6dfa:eth2: up
> > > 
> > > So there appears to be some difference in behaviour between
> > > having
> > > an
> > > explicit node address and using the default. Unfortunately our
> > > application
> > > relies on setting the node addresses.
> > I do this many times a day, without any problems. If there would be
> > any time difference, I would expect the 'auto configurable' version
> > to be slower, because it involves a DAD step.
> > Are you sure you don't have any other nodes running in your system?
> > 
> > ///jon
> > 
> Nope the two nodes are connected back to back. Does the number of
> Ethernet interfaces make a difference? As you can see I've got 3 on
> each node. One is completely disconnected, one is for booting over
> TFTP
> Â(only used by U-boot) and the other is the USB Ethernet I'm using
> for
> testing.
> 

So I can still reproduce this on nodes that only have one network
interface and are the only things connected.

I did find one thing that helps

diff --git a/net/tipc/discover.c b/net/tipc/discover.c
index c138d68e8a69..49921dad404a 100644
--- a/net/tipc/discover.c
+++ b/net/tipc/discover.c
@@ -358,10 +358,10 @@ int tipc_disc_create(struct net *net, struct
tipc_bearer *b,
ÂÂÂÂÂÂÂÂtipc_disc_init_msg(net, d->skb, DSC_REQ_MSG, b);
Â
ÂÂÂÂÂÂÂÂ/* Do we need an address trial period first ? */
-ÂÂÂÂÂÂÂif (!tipc_own_addr(net)) {
+//ÂÂÂÂÂif (!tipc_own_addr(net)) {
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂtn->addr_trial_end = jiffies + msecs_to_jiffies(1000);
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂmsg_set_type(buf_msg(d->skb), DSC_TRIAL_MSG);
-ÂÂÂÂÂÂÂ}
+//ÂÂÂÂÂ}
ÂÂÂÂÂÂÂÂmemcpy(&d->dest, dest, sizeof(*dest));
ÂÂÂÂÂÂÂÂd->net = net;
ÂÂÂÂÂÂÂÂd->bearer_id = b->identity;

I think because with pre-configured addresses the duplicate address
detection is skipped the shorter init phase is skipped. Would is make
sense to unconditionally do the trial step? Or is there some better way
to get things to transition with pre-assigned addresses.