Re: Problems with Intel e100 driver on new MIPS port, was: Advice needed WRT very slow nfs in new port...

[David Daney <ddaney@avtrex.com>]

Michael Stickel wrote:
> M. Warner Losh wrote:
>
> > In message: <42C359F8.4060000@avtrex.com>
> >            David Daney <ddaney@avtrex.com> writes:
> > : M. Warner Losh wrote:
> > : > In message: <42C34C4D.9020902@avtrex.com>
> > : >             David Daney <ddaney@avtrex.com> writes:
> > : > : Does anyone have any idea what would cause 1000mS delay?
> > : > : > That's remarkably close to 1s.  This often indicates that the 
> > transmit
> > : > of your next packet is causing the receive buffer to empty.  This is
> > : > usually due to blocked interrupts, or a failure to enable interrupts.
> > : > : : But I observe ever increasing counts for the device in 
> > /proc/interrupts. :   So the interrupts are working somewhat.
> > Are you sure that you've routed the interrupts correctly?  Maybe those
> > interrupts are 'really' for a different device....
> >  
> Add some debugging to the interrupt routine of the e100 and see what 
> happens.
The interrupt routine is getting called each time a packet is received.

It looks like packets are not being transmitted until the interrupt for 
the the received packet is received.
If I ping the board at different intervals the round trip time is always 
almost exactly equal to the ping interval.  So if I ping every 50mS the 
round trip time is 50mS, ping every 200mS gives a RTT of 200mS, etc.
Any more ideas?

I am thinking that perhaps the CPU write-back-queue is interfearing with 
writes to the NIC's registers.  Perhaps I will try to disable it.
David Daney.