[openib-general] SDP message loss

[Majumder, Rajib]

hi tom, 

In case of RNR nack/PSN error nack/fatal error nack and the data source's RC QP's retry count is exhausted, what would be the fate of the packet?

thanks. 

rajib 

-----Original Message-----
From: Tom Duffy [mailto:tomduffy at gmail.com]
Sent: 05 September 2005 11:16
To: Majumder, Rajib
Cc: openib-general at openib.org
Subject: Re: [openib-general] SDP message loss


On 9/4/05, Majumder, Rajib <rajib.majumder at csfb.com> wrote:
> hi,
> 
> We are doing some proof of concept over SDP. During that we noticed that not all messages are received by the data sink.
> Can there by a message loss in SDP? If yes, what could be the possible reasons?

No, there shouldn't be a loss.  SDP uses the reliable connected mode
of Infiniband.  It is possible that there is bug in the software, but
the hardware should be delivering all of the bits.

> In this case, is there any diagnostic tool, eg. a packet filter, that can give us some idea?

Have you tried some of the simpler test ulps?  Or DAPL which also uses
RC?  That would help narrow it down to SDP.

> We are using RHAS 3.0.

Hrm, that is old and 2.4-based.  Not that it should really matter as I
am assuming you are compilng your own kernel...and got all the 2.6
userland stuff on there.  But, in any event, that shouldn't have any
impact on this problem.

-tduffy

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