Re: weird network problems on current since 10/28/2012

On 04.11.2012 21:15, Andreas Tobler wrote:
> On 04.11.12 14:57, Andre Oppermann wrote:
>> On 04.11.2012 13:11, Kim Culhan wrote:
>>> On Sun, November 4, 2012 6:21 am, Dimitry Andric wrote:
>>>> On 2012-11-04 02:13, Manfred Antar wrote:
>>>>> At 03:29 PM 11/3/2012, Adrian Chadd wrote:
>>>> After the commit, there was a small discussion thread on svn-src-head_at_
>>>> about the possible problems with the approach.  Maybe you are
>>>> experiencing those?
>>>>
>>>> As the commit message says, you should be able to turn the feature off
>>>> using:
>>>>
>>>>      sysctl net.inet.tcp.experimental.initcwnd10=0
>>>>
>>>> Can you please try that, and see if the problems go away?
>>>
>>> FWIW this did not make the problem go away on 2 machines.
>>
>> Yes, this very much looks like the same problem as in PR/173309.
>>
>> Please try the attached patch.  It fixes the connection hang issue.
>> There may be a second issue I debugging currently base on the feedback
>> from Fabian Keil.
>
> I jump into this thread since I have a similar network issue.
>
> My scenario:
>
> 'make installkernel DESTDIR=/netboot/test' to a nfs mounted drive.
> The nfs drive on the server is an ufs fs. No zfs.
>
> Up to r242261 I can install the kernel (or world) in a fluent way to the
> nfs destination.
>
>>From r242262 it doesn't work smooth. I have stalls, sometimes my
> patience is not enough and I kill the process.
>
> I tried 242266 with the above mentioned patch. No real success.
>
> How can I help/test?

Please try the attach patch instead of the above mentioned one.

-- 
Andre

Index: netinet/tcp_output.c
===================================================================
--- netinet/tcp_output.c        (revision 242577)
+++ netinet/tcp_output.c        (working copy)
_at__at_ -228,7 +228,7 _at__at_
         tso = 0;
         mtu = 0;
         off = tp->snd_nxt - tp->snd_una;
-       sendwin = min(tp->snd_wnd, tp->snd_cwnd);
+       sendwin = ulmax(ulmin(tp->snd_wnd - off, tp->snd_cwnd), 0);

         flags = tcp_outflags[tp->t_state];
         /*
_at__at_ -249,7 +249,7 _at__at_
             (p = tcp_sack_output(tp, &sack_bytes_rxmt))) {
                 long cwin;

-               cwin = min(tp->snd_wnd, tp->snd_cwnd) - sack_bytes_rxmt;
+               cwin = ulmin(tp->snd_wnd - off, tp->snd_cwnd) - sack_bytes_rxmt;
                 if (cwin < 0)
                         cwin = 0;
                 /* Do not retransmit SACK segments beyond snd_recover */
_at__at_ -355,7 +355,7 _at__at_
                          * sending new data, having retransmitted all the
                          * data possible in the scoreboard.
                          */
-                       len = ((long)ulmin(so->so_snd.sb_cc, tp->snd_wnd)
+                       len = ((long)ulmin(so->so_snd.sb_cc, tp->snd_wnd - off)
                                - off);
                         /*
                          * Don't remove this (len > 0) check !