Bug#572201: forcedeth driver hangs under heavy load

[Eric Dumazet <eric.dumazet@gmail.com>]

Le mardi 13 avril 2010 à 15:49 +0100, stephen mulcahy a écrit :
> Eric Dumazet wrote:
> > Le mardi 13 avril 2010 à 15:27 +0100, stephen mulcahy a écrit :
> >> Ok, I've tried both of the following with my reproducer
> >>
> >> 1. ethtool -K eth0 tso off
> >>
> >> RESULT: reproducer causes multiple hosts to be come unresponsive on 
> >> first run.
> >>
> >> 2. ethtool -K eth0 tx off
> >>
> >> RESULT: reproducer runs three times without any hosts becoming unresponsive.
> >>
> >> -stephen
> > 
> > Thanks Stephen !
> > 
> > Now some brave fouls to check the 6410 lines of this driver ? ;)
> > 
> > Question of the day : Why TSO is broken in forcedeth ?
> > Is it generically broken or is it broken for specific NICS ?
> > 
> 
> Actually, it is only when tx-checksumming is turned off that the problem 
>   doesn't occur (so I'm not sure TSO is the problem).
> 
> Additionally, a google also turns up this existing Debian bug 
> http://bugs.debian.org/506419 which seems to be related.
> 
> -stephen
> 

I am scratching my head, but I thought you told me that

ethtool -K eth0 tso off
ethtool -K eth0 tx on 

was working ?

And, given that when you perform "ethtool -K eth0 tx off", TSO is
automatically off...

tx checksums work, TSO doesnt work, therefore TSO is broken ?