[Openib-windows] Added ability to change IPoIB mtu size

[Alex Estrin]

Hi,

> -----Original Message-----
> From: Yossi Leybovich [mailto:sleybo at dev.mellanox.co.il]
> Sent: Wednesday, November 29, 2006 11:11 AM
> To: Alex Estrin; Yossi Leybovich
> Cc: openib-windows at openib.org
> Subject: RE: [Openib-windows] Added ability to change IPoIB mtu size
> 
> 
> Hi
> 
> Why do we need that?
> Just update the inf and the driver will load. ( or you can 
> fake the registry
> key ...).

- no updated INF file handy. 
- Intentionally removed key.

> If we go to this direction we should give default values for all the
> registry 
> keys why just to the payload ?
Yes,I think that would be the best to have all default values for all the keys.
I assume almost all other IB stack capabilities depend on IPoIB functionality,
so it wouldn't be too much to expect it to be as foolproof as possible.
What do you think?

> Thanks
> Yossi 
> 
> > -----Original Message-----
> > From: openib-windows-bounces at openib.org 
> > [mailto:openib-windows-bounces at openib.org] On Behalf Of Alex Estrin
> > Sent: Wednesday, November 29, 2006 6:05 PM
> > To: Yossi Leybovich
> > Cc: openib-windows at openib.org
> > Subject: Re: [Openib-windows] Added ability to change IPoIB mtu size
> > 
> > Hi Yossi,
> > 
> > This patch would allow IPoIB to run even if for any reason 
> > payload mtu parameter is missing.
> > Please review.
> > 
> > Thanks,
> > Alex
> > 
> > Index: ipoib_driver.c
> > ===================================================================
> > --- ipoib_driver.c	(revision 552)
> > +++ ipoib_driver.c	(working copy)
> > @@ -533,9 +533,13 @@
> >  	{
> >  		IPOIB_PRINT_EXIT( TRACE_LEVEL_ERROR, IPOIB_DBG_ERROR,
> >  			("PayloadMtu parameter missing. Use the 
> > default.\n") );
> > -		return status;
> > +		p_adapter->params.payload_mtu = MAX_PAYLOAD_MTU;
> > +		status = NDIS_STATUS_SUCCESS;
> >  	}
> > -	p_adapter->params.payload_mtu = 
> > p_param->ParameterData.IntegerData;
> > +	else
> > +	{
> > +		p_adapter->params.payload_mtu = 
> > p_param->ParameterData.IntegerData;
> > +	}
> >  	p_adapter->params.xfer_block_size = (sizeof(eth_hdr_t) 
> > + p_adapter->params.payload_mtu);
> >  	NdisReadNetworkAddress( &status, &mac, &len, h_config );
> > 
> > > -----Original Message-----
> > > From: openib-windows-bounces at openib.org 
> > > [mailto:openib-windows-bounces at openib.org]On Behalf Of 
> > Yossi Leybovich
> > > Sent: Wednesday, November 22, 2006 3:29 AM
> > > To: Fabian Tillier; Anatoly Lisenko
> > > Cc: openib-windows at openib.org
> > > Subject: Re: [Openib-windows] Added ability to change 
> IPoIB mtu size
> > > 
> > > 
> > >  
> > > 
> > > > -----Original Message-----
> > > > From: Fabian Tillier [mailto:ftillier.sst at gmail.com]
> > > > Sent: Wednesday, November 22, 2006 9:13 AM
> > > > To: Anatoly Lisenko
> > > > Cc: Yossi Leybovich; openib-windows at openib.org
> > > > Subject: Re: [Openib-windows] Added ability to change 
> > IPoIB mtu size
> > > > 
> > > > Hi folks,
> > > > 
> > > > On 11/19/06, Anatoly Lisenko <anatolyl at voltaire.com> wrote:
> > > > >
> > > > > Hi Yossi,
> > > > >
> > > > > This patch add the ability to change MTU size in IPoIB.
> > > > >
> > > > > Please review.
> > > > >
> > > > > Thanks,
> > > > >
> > > > > Anatoly
> > > > 
> > > > It would be nice to have an explanation of what problem 
> > patches are 
> > > > trying to solve.  I assume this is done to enable 
> virtualization 
> > > > over IPoIB, which requires network packets to be ethernet 
> > MTU-sized.
> > > > 
> > > > I didn't have a chance to look at the patch, but have these
> > > thoughts.
> > > > Limiting the MTU reported to the OS works fine for 
> > outbound packets, 
> > > > but care must be exercised for inbound packets.
> > > > 
> > > > 1. The buffers posted to the receive queue must be the full
> > > > 2048 byte IB MTU so that the IPoIB driver can receive 
> any packets 
> > > > sent to it without hitting a protection error due to 
> > overrunning the 
> > > > receive buffers.
> > > > 2. If a buffer larger than the configured MTU is 
> > received, it must 
> > > > be reported to the OS somehow.  I don't know what's 
> > required to do 
> > > > this, whether you create a new IP header for the data 
> beyond the 
> > > > first, or whatnot, but it must be done in such a way that 
> > subsequent 
> > > > packets don't cause issues with sequence numbers.  This 
> > doesn't seem 
> > > > like a simple thing to do right, let alone in a performant way.
> > > > 
> > > Cant we just drop the packets and add that to the statiscs 
> > of packet 
> > > discards?
> > > Wny how I will check that in the code.
> > > 
> > > > Cheers,
> > > > 
> > > > - Fab
> > > > 
> > > 
> > > _______________________________________________
> > > openib-windows mailing list
> > > openib-windows at openib.org
> > > http://openib.org/mailman/listinfo/openib-windows
> > > 
> > > 
> > 
> 
>