I'm not all that familiar with the MTU negotiation protocol either. Note that the CM or SDP should be using ib_query_port() to get the max MTU the device/port supports.
My main concern is the device specific code which is compiled into sdp_cm_path_complete() to reduce the MTU to something less than the maximum to work around a performance bug. I was proposing to make this a module parameter but perhaps a better solution would be some interface where the device driver can set it or SDP queries the device for the optimum value. On Wed, 2006-02-15 at 23:24 +0200, Michael S. Tsirkin wrote: > Quoting r. Ralph Campbell <[EMAIL PROTECTED]>: > > Subject: [PATCH] change Mellanox SDP workaround to a moduleparameter > > > > This patch changes the hardwired MTU limit of 1024 in SDP > > into a module parameter so it can be disabled for HCAs > > without the RC performance problem. > > > > Signed-off-by: Ralph Campbell <[EMAIL PROTECTED]> > > I thought about it some more: what happens if nodes with different > max MTU values try to connect? > > My understanding of the spec: > > - passive side should send REJ indicating error and passing the > maximum MTU it supports > - active side should retry the connection with a lower MTU > > Right? > By the way, this handling seems to be missing in CMA. > -- Ralph Campbell <[EMAIL PROTECTED]> _______________________________________________ openib-general mailing list [email protected] http://openib.org/mailman/listinfo/openib-general To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general
