Date:   Sun, 4 Aug 2019 23:04:39 +0000
From:   Chris Packham <Chris.Packham@...iedtelesis.co.nz>
To:     "jon.maloy@...csson.com" <jon.maloy@...csson.com>,
        "tipc-discussion@...ts.sourceforge.net" 
        <tipc-discussion@...ts.sourceforge.net>
CC:     "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: Slowness forming TIPC cluster with explicit node addresses

On Sun, 2019-08-04 at 21:53 +0000, Jon Maloy wrote:
> 
> > 
> > -----Original Message-----
> > From: netdev-owner@...r.kernel.org <netdev-owner@...r.kernel.org>
> > On
> > Behalf Of Chris Packham
> > Sent: 2-Aug-19 01:11
> > To: Jon Maloy <jon.maloy@...csson.com>; tipc-
> > discussion@...ts.sourceforge.net
> > Cc: netdev@...r.kernel.org; linux-kernel@...r.kernel.org
> > Subject: Re: Slowness forming TIPC cluster with explicit node
> > addresses
> > 
> > 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@...r.kernel.org <netdev-
> > owner@...r.kernel.org>
> > > 
> > > > 
> > > > > 
> > > > > On Behalf Of Chris Packham
> > > > > Sent: 25-Jul-19 19:37
> > > > > To: tipc-discussion@...ts.sourceforge.net
> > > > > Cc: netdev@...r.kernel.org; linux-kernel@...r.kernel.org
> > > > > 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 use tipc link list
> > > > > 
> > > > > [root@...e-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@...e-6 ~]# tipc link list
> > > > > broadcast-link: up
> > > > > 1001006:eth2-1001005:eth2: up
> > > > > 
> > > > > [root@...e-5 ~]# 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@...e-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
> > >  (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,
> >         tipc_disc_init_msg(net, d->skb, DSC_REQ_MSG, b);
> > 
> >         /* Do we need an address trial period first ? */
> > -       if (!tipc_own_addr(net)) {
> > +//     if (!tipc_own_addr(net)) {
> >                 tn->addr_trial_end = jiffies +
> > msecs_to_jiffies(1000);
> >                 msg_set_type(buf_msg(d->skb), DSC_TRIAL_MSG);
> > -       }
> > +//     }
> >         memcpy(&d->dest, dest, sizeof(*dest));
> >         d->net = net;
> >         d->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.
>
> I am on vacation until the end of next-week, so I can't give you any
> good analysis right now.

Thanks for taking the time to respond.

> To do the trial step doesn’t make much sense to me, -it would only
> delay the setup unnecessarily (but with only 1 second).
> Can you check the initial value of addr_trial_end when there a pre-
> configured address?

I had the same thought. For both my devices 'addr_trial_end = 0' so I
think tipc_disc_addr_trial_msg should end up with trial == false

> 
> ///jon
> 

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