[ofa-general] Receiving Unknown packets at regular interval

Hal Rosenstock hrosenstock at xsigo.com
Mon May 19 04:47:23 PDT 2008 

Sumit,

On Mon, 2008-05-19 at 15:25 +0530, Sumit Gaur - Sun Microsystem wrote:
> Hi
> I have an issue while my program interacting with OFED umad library.

Are you referring to libibumad ?

> I have two 
> separate threads one for sending SMP,GMP packets and another to receive 
> response. Things are working fine but during the whole process I keep receiving 
> packets with unknown tid apart from correct response.

What's the exact message ?

>  Is it a correct behavior.

It could be; there's not enough info as to what is going on. It could be
some unsolicited message (e.g. from SM) comes in during your
transactions. Can you see what MADs are incoming ? One way to do that
would be to run madeye.

> If yes how I could avoid them ?

Not sure what you are seeing yet.

-- Hal

> Thanks and Regards
> sumit
> 
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> > Today's Topics:
> > 
> >    1. Re:  [PATCH] IB/core: handle race between elements in	qork
> >       queues after event (Roland Dreier)
> >    2. Re:  RDS flow control (Steve Wise)
> >    3. Re:  RDS flow control (Olaf Kirch)
> >    4. Re:  RDS flow control (Steve Wise)
> >    5. Re:  RDS flow control (Olaf Kirch)
> >    6. Re:  [PATCH 3/3] IB/ipath - fix RDMA read response	sequence
> >       checking (Roland Dreier)
> >    7.  Re: [PATCH][INFINIBAND]: Make ipath_portdata work with
> >       struct pid * not pid_t. (Roland Dreier)
> >    8. Re:  bitops take an unsigned long * (Roland Dreier)
> > 
> > 
> > ----------------------------------------------------------------------
> > 
> > Message: 1
> > Date: Tue, 13 May 2008 10:41:39 -0700
> > From: Roland Dreier <rdreier at cisco.com>
> > Subject: Re: [ofa-general] [PATCH] IB/core: handle race between
> > 	elements in	qork queues after event
> > To: Moni Shoua <monis at Voltaire.COM>
> > Cc: Olga Stern <olgas at voltaire.com>,	OpenFabrics General
> > 	<general at lists.openfabrics.org>
> > Message-ID: <adatzh2ksoc.fsf at cisco.com>
> > Content-Type: text/plain; charset=us-ascii
> > 
> >  > Can we please go on with this patch? We would like to see it in the next kernel.
> > 
> > I still don't get why this is important to you.  Is there a concrete
> > example of a situation where this actually makes a measurable difference?
> > 
> > We need some justification for adding this locking complexity beyond "it
> > doesn't hurt."  (And also of course we need it fixed so there aren't races)
> > 
> >  - R.
> > 
> > 
> > ------------------------------
> > 
> > Message: 2
> > Date: Tue, 13 May 2008 12:58:11 -0500
> > From: Steve Wise <swise at opengridcomputing.com>
> > Subject: Re: [ofa-general] RDS flow control
> > To: Richard Frank <richard.frank at oracle.com>
> > Cc: rds-devel at oss.oracle.com, general at lists.openfabrics.org
> > Message-ID: <4829D6B3.5080900 at opengridcomputing.com>
> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> > 
> > Richard Frank wrote:
> > 
> >>Steve Wise wrote:
> >>
> >>>Olaf Kirch wrote:
> >>>
> >>>>On Monday 12 May 2008 18:57:38 Jon Mason wrote:
> >>>> 
> >>>>
> >>>>>As part of my effort to get RDS working for iWARP, I will be 
> >>>>>working on the RDS flow control.  Flow control is needed for iWARP 
> >>>>>due to the fact that iWARP connections terminate if there is no 
> >>>>>posted recv for an incoming packet.  IB connections do not have 
> >>>>>this limitation if setup in a certain way.  In its current 
> >>>>>implementation, RDS sets the connection attribute rnr_retry to 7.  
> >>>>>This causes IB to retransmit until there is a posted recv buffer.     
> >>>>
> >>>>I think for the initial implementation, it is fine for iWARP to just
> >>>>fail the connect when that happens, and re-establish the connection.
> >>>>
> >>>>If you use reasonable defaults for the send and recv queues, receiver
> >>>>overruns should be relatively rare.
> >>>>
> >>>>Once everything else works, let's revisit the flow control part.
> >>>>
> >>>>  
> >>>
> >>>I _think_ you'll hit this quickly with one-way flows.  Send 
> >>>completions for iWARP only mean the user's buffer can be reused.  Not 
> >>>that its placed at the remote peer or in the remote user's buffer.
> >>>
> >>
> >>Let's see what happens - anyway - this could be solved in an IWARP 
> >>extension to RDS  - right ?
> > 
> > 
> > 
> > Yes, by adding flow control.  And it could be iwarp-specific if you 
> > want.    I would not suggest relying on connection termination and 
> > re-establishment as the way to handle this :).
> > 
> > 
> > 
> > 
> >>>But perhaps I'm wrong.  Jon, maybe you should try to hit this with IB 
> >>>and rnr_retry == 0 using the rds perf tools?
> >>>Also "the everything else" part depends on remove fmr usage.  I'm 
> >>>working on the new RDMA memory verbs allowing fast registration of 
> >>>physical memory via a send WR.  To support iWARP we need to remove 
> >>>the fmr usage from RDS.   The idea was to replace fmrs with the new 
> >>>fastreg verbs.   Thoughts?
> >>>
> >>
> >>What does "fast" imply here - how does this compare to the performance 
> >>of FMRs ?
> > 
> > 
> > 
> > Don't know yet, but probably as fast. 
> > 
> > 
> >>Why would not push memory window creation into the RDS transport 
> >>specific implementations ?
> > 
> > 
> > Isn't it already transport-specific?  IE you don't need FMRs for TCP.  
> > (I'm ignorant on the specifics of the implementation at this point, so 
> > please excuse any dumb statements :)
> > 
> > 
> > 
> >>Changing the API may be OK - if we retain the performance we have with 
> >>IB.
> > 
> > 
> > 
> > I assume nothing would fly that regresses IB performance.  Worst case, 
> > you have an iwarp-specific RDS transport like you do for TCP, I guess.  
> > Hopefully though, IB + iWARP will be a common transport.
> > 
> > 
> > 
> >>>Stay tuned for the new verbs API RFC...
> >>>
> >>>Steve.
> >>>_______________________________________________
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> >>>general at lists.openfabrics.org
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> > 
> > 
> > 
> > ------------------------------
> > 
> > Message: 3
> > Date: Tue, 13 May 2008 20:04:00 +0200
> > From: Olaf Kirch <okir at lst.de>
> > Subject: Re: [ofa-general] RDS flow control
> > To: Steve Wise <swise at opengridcomputing.com>
> > Cc: rds-devel at oss.oracle.com, general at lists.openfabrics.org
> > Message-ID: <200805132004.01371.okir at lst.de>
> > Content-Type: text/plain;  charset="iso-8859-1"
> > 
> > On Tuesday 13 May 2008 19:58:11 Steve Wise wrote:
> > 
> >>Yes, by adding flow control.  And it could be iwarp-specific if you 
> >>want.    I would not suggest relying on connection termination and 
> >>re-establishment as the way to handle this :).
> > 
> > 
> > No, not in the long term. But let's hold off on the flow control stuff
> > for a little - I would first like to finish my patch set and hand it
> > out for you folks to bang on it, rather than the other way round.
> > Okay with you guys?
> > 
> > 
> >>I assume nothing would fly that regresses IB performance.  Worst case, 
> >>you have an iwarp-specific RDS transport like you do for TCP, I guess.  
> >>Hopefully though, IB + iWARP will be a common transport.
> > 
> > 
> > If it turns out that way, fine. If iWARP ands up sharing 80% of the
> > code with IB except the RDMA specific functions, I think that's
> > very much acceptable, too.
> > 
> > Olaf
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