Re: Python 2 and test/vm/netbsd

[Eduardo Habkost]

On Fri, Oct 18, 2019 at 12:44:39PM +0200, Gerd Hoffmann wrote:
>   Hi,
> 
> > > Running with V=1, I see packages being downloaded at reasonable speeds, 
> > > but
> > > there's a huge interval (of various minutes) between each package 
> > > download.
> > 
> > I've found the cause for the slowness I'm seeing: for each file
> > being downloaded, the guest spents at least 75 seconds trying to
> > connect to the IPv6 address of ftp.NetBSD.org, before trying
> > IPv4.
> 
> Ah, that nicely explains why it worked just fine for me.  First, I have
> a local proxy configured so the installer isn't going to connect to
> ftp.NetBSD.org directly.  Second I have IPv6 connectivity.
> 
> > I don't know if this is a NetBSD bug, or a slirp bug.
> 
> Both I'd say ...
> 
> First, by default slirp should not send IPv6 router announcements
> to the user network if the host has no IPv6 connectivity.
> 
> Second, the recommended way to connect is to try ipv4 and ipv6 in
> parallel, then use whatever connects first.  Web browsers typically
> do it that way.  wget and curl don't do that though, they try one
> address after the other, and I guess this is where the delay comes
> from ...

In addition to that, the connect() error should be generating a
ICMP6_UNREACH message, and I'd expect the NetBSD guest to notice
it instead of waiting for timeout.

-- 
Eduardo