[systemd-devel] network-online.target time

[Peter Morrow]

On Wed, 2020-05-06 at 17:51 +0200, Lennart Poettering wrote:
> On Mi, 06.05.20 15:50, Peter Morrow (
> Peter.Morrow at microsoft.com
> ) wrote:
> 
> > On Wed, 2020-05-06 at 17:39 +0200, Lennart Poettering wrote:
> > > On Mi, 22.04.20 14:44, Peter Morrow (
> > > Peter.Morrow at microsoft.com
> > > 
> > > ) wrote:
> > > 
> > > > Hi Folks,
> > > > 
> > > > I'm trying to optimise our boot process and have started to
> > > > look at
> > > > the time it takes for the network to come up (a single
> > > > interface to
> > > > be
> > > > routable) when using systemd-networkd:
> > > > 
> > > > Can anyone offer any suggestions for where I should look to try
> > > > to
> > > > speed things up here?
> > > 
> > > Turn on debug logging for networkd. it should tell you what it is
> > > doing, and the timestamps should allow you to determine what
> > > precisely
> > > is being waited for.
> > 
> > Thanks. Yes - I ended up doing this and it turned out much of the
> > additional time is down to ipv6 interface
> > configuration.  Specifically
> > ipv6 link local duplicate address detection.
> 
> You can turn that off if you like: IPv6DuplicateAddressDetection=

This option worked well when I tried it (total time came down to
~700ms) but unfortunately disabling it entirely isn't an option.

FWIW setting CONFIG_IPV6_OPTIMISTIC_DAD=y in the kernel is providing a
good middle ground.

Peter.


> Lennart
> 
> --
> Lennart Poettering, Berlin