Re: BQL support in gianfar causes network hickup

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

On Tue, 2012-11-27 at 10:36 +0100, Keitel, Tino (ALC NetworX GmbH)
wrote:
> On Mo, 2012-11-26 at 09:17 -0800, Eric Dumazet wrote:
> > On Mon, 2012-11-26 at 18:08 +0100, Keitel, Tino (ALC NetworX GmbH)
> > wrote:
> > > On Mo, 2012-11-26 at 08:34 -0800, Eric Dumazet wrote:
> > > > On Mon, 2012-11-26 at 11:01 +0100, Tino Keitel wrote:
> > > > > On Sat, Nov 24, 2012 at 15:43:36 -0800, Eric Dumazet wrote:
> > > > > 
> > > > > [...]
> > > > > 
> > > > > > Hmm, I wonder if BQL makes a particular bug showing more often.
> > > > > > 
> > > > > > I see gianfar uses a very small watchdog_timeo of 1 second, while many
> > > > > > drivers use 5 seconds.
> > > > > > 
> > > > > > What happens if you change this to 5 seconds ?
> > > > > 
> > > > > I still got the trace and a failing ptp client.
> > > > > 
> > > > 
> > > > Thanks. Is this bug easy to trigger ?
> > > > 
> > > > I suspect a core issue and a race, likely to happen on your (non x86)
> > > > hardware
> > > > 
> > > > Could you add the following debugging patch ?
> > > 
> > > No visible difference:
> > 
> > OK it seems you trigger the problem fast !
> > 
> > Please try the following as well :
> 
> Hi,
> 
> yes, it can be triggered within 2 minutes.
> 
> The patch makes no difference:

Can you reproduce the problem using a single cpu ?