Date: Thu, 22 Nov 2001 09:31:57 -0800 From: Luigi Rizzo <rizzo@aciri.org> To: rick norman <rnorman@ikaika.com> Cc: freebsd-hackers@freebsd.org Subject: Re: dummynet "pipe show" problem Message-ID: <20011122093157.B47061@iguana.aciri.org> In-Reply-To: <3BFC3299.E7DBA702@ikaika.com> References: <3BDEF5C5.F5D604C2@lmco.com> <20011030113914.H9665@iguana.aciri.org> <3BFC3299.E7DBA702@ikaika.com>
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On Wed, Nov 21, 2001 at 03:02:49PM -0800, rick norman wrote:
> Hi,
> I'm still running into lots of problems with this on 4.3. Is it neccessary
> to introduce a delay in the pipe ? Would a delay of zero work ?
> Has this been fixed in 4.4 ?
Thinking about it, I believe it might be a problem with
the routing code, not with dummynet, and it has to do with the
fact that you delete and reassign the address to the
loopback interface.
I am almost sure that 4.4 would cure the problem, because
that problem was fixed before 4.4.
cheers
luigi
> Rick
>
> Luigi Rizzo wrote:
>
> > On Tue, Oct 30, 2001 at 10:47:33AM -0800, rick norman wrote:
> > > Hi,
> > > I have enclosed a short piece of code that seems to
> > > reproduce the problem after 5 to 10 minutes.
> > > I am running 4.3 freebsd off the release cd's.
> > > Pretty much the generic kernel except for the
> > > addition of dummynet and ipfw. My platform
> > > is a dell dimension 4100 with 1ghz p3, though
> > > I doubt that is relevant. To reproduce the problem,
> > > compile and run the enclosed code in one window.
> > > In another window su to root and run "ping -s 1024 -f 127.0.42.1".
> > > As you will see, the code reports the gowing byte count as one
> > > would expect. Walk away for 5 to 10 minutes and when you come
> > > back you should see the state I'm talking about. The flood ping stream
> >
> > It _might_ be a locking problem due to the frequent
> > reconfigurations of the pipe -- i think there was some
> > fix of this kind related to ipfw commands between 4.3 and 4.4.
> > I will see if i can reproduce the problem locally (but i have
> > 4.4).
> >
> > You are using dummynet in a very peculiar way:
> > more precisely, your pipe does not introduce any delay,
> > and this excludes the scheduler which is part of dummynet.
> > Also you are using the same pipe for icmp requests
> > and replies, which are generated within the kernel, so
> > the behaviour should be quite deterministic in this
> > respect.
> >
> > thanks for the report
> >
> > luigi
> >
> > > Thanks,
> > > Rick
> > >
> > > ----------------------cut--------------------------------------------
> > >
> > > main() {
> > > int i;
> > >
> > > restart:
> > > system("ifconfig lo0 -alias 127.0.42.1");
> > > system("ifconfig lo0 alias 127.0.42.1 netmask 255.255.255.0");
> > > system("ipfw -f flush");
> > > system("ipfw pipe 1 delete");
> > > system("ipfw add pipe 1 ip from 127.0.42.0/24 to any in");
> > >
> > > for(i=0;i<5;i++) {
> > > system("ipfw pipe 1 config queue 2048Bytes");
> > > sleep(1);
> > > system("ipfw pipe 1 show");
> > > }
> > >
> > > goto restart;
> > > }
> > >
> > > --------------------cut--------------------------------------
> > >
> > >
> > >
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> >
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