Re: The rc.d mess strikes back

From: Brooks Davis <brooks_at_freebsd.org>
Date: Wed, 4 Mar 2009 10:49:53 -0600
On Wed, Mar 04, 2009 at 12:04:06AM -0800, Garrett Cooper wrote:
> On Tue, Mar 3, 2009 at 10:12 PM, Mike Telahun Makonnen
> <mmakonnen_at_gmail.com> wrote:
> > On Tue, Mar 3, 2009 at 9:03 PM, Brooks Davis <brooks_at_freebsd.org> wrote:
> >>
> >> I don't have much time to debug this, but I've not had problems with
> >> services starting too early on the systems I've been running with async
> >> dhcp. ?If there is a problem with the wait process we need to actually
> >> debug it. ?If the wait for a route/running interface isn't sufficent we
> >> should try to figure out what is. ?Synchronous dhcp sucks and yeilds
> >> justifed user complaints so it would be nice to kill it off. ?I switched
> >> the default because it worked for me and I hoped that people would help
> >> find and fix edge cases.
> >
> > Can you elaborate why synchronous DHCP sucks ?
> 
> The only reason I could see is bringup time. Am I correct in this assumption?

If you use synchronous DHCP then every interface that wants to try to
get a DHCP address if it has link needs to run through the full link
timeout at boot.  On a laptop this is annoying and generally pointless.
The changes to defaultroute to wait for a default route to be set mean
that you consolidate the wait in one location and you don't waste time
starting dhclient on interfaces until a link exists (or an association
is made for wlan devices).  There may well be something better to wait
or a need for a longer timeout in some environments.  It's also quite
possible that we have an ordering problem and need to move some more
things after defaultroute or move the checks to a different location.

-- Brooks

Received on Wed Mar 04 2009 - 15:51:12 UTC

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