[openib-general] Some Missing Features from mthca/user MAD ac cess

[Eitan Zahavi]

I'm sorry if I did not explain myself very well.
I did not mean to say another application will respond to SMInfo.
Nor I claimed that SMInfo should be used for anything else but SM to SM
discovery.
 
I only referred to the idea that one can set the SM bit by inspecting the
mask of registrations to mad filtering requests.
I assume that one can register by supplying a mask. Now - you probably do
not have any control over the mask an arbitrary application might use. So
depending on it not to set the SMInfo bit (even though it will not process
the mads) is too risky in my mind.
 
However, from your response it seems like only one client is allowed to
register as the receiver for incoming requests of specific attribute. Is
this correct? If this is the case then a careless application can block the
SM from obtaining any SMInfo or other queries. 
 
Eitan Zahavi
Design Technology Director
Mellanox Technologies LTD
Tel:+972-4-9097208
Fax:+972-4-9593245
P.O. Box 586 Yokneam 20692 ISRAEL
 
-----Original Message-----
From: shaharf [mailto:shaharf at voltaire.com] 
Sent: Monday, January 10, 2005 6:56 PM
To: Eitan Zahavi; Michael S. Tsirkin; Roland Dreier
Cc: openib-general at openib.org
Subject: RE: [openib-general] Some Missing Features from mthca/user MAD
access
 
Eitan, the main (and only) purpose of the IS_SM bit is for SM to SM
coordination. As a matter of fact it means that when discavering a port with
this bit you have to query it with sminfo to see if he is the master or
maybe it should be the master. There is not other use. Having an application
other then the SM respond to the sminfo would not work in the current
scheme.  As a matter of fact it maybe catastrophic - meaning it may lead to
multiple masters SM in the subnet!!! 
 
I really don't understand what resources you refer to. I think I know the
OpenSM pretty well but maybe I have new things to learn. Please enlighten
me.
Ref-counting too is useless. There should be only one SM on the port. I see
not reason to change that.
 
Shahar
 
  _____  

From: Eitan Zahavi [mailto:eitan at mellanox.co.il] 
Sent: Monday, January 10, 2005 6:43 PM
To: shaharf; Eitan Zahavi; Michael S. Tsirkin; Roland Dreier
Cc: openib-general at openib.org
Subject: RE: [openib-general] Some Missing Features from mthca/user MAD
access
 
Shahar> Yes, but when you want to respond to attributes you have to specify
a mask. Using that mask you can register to any attribute set you want.
Yes, but if the application (that is not an SM) will use a mask that has the
sminfo set - it will be considered an SM.
I would prefer having the SMBit stay on when the SM dies then having
spurious SMBit transitions.
It will take more resources from the SM when these bits will start to
change.
Also you will need to start ref-counting on the port since several apps can
share it and they will not obey the rule for not masking the sminfo if they
are not SMs.
 
Eitan Zahavi
Design Technology Director
Mellanox Technologies LTD
Tel:+972-4-9097208
Fax:+972-4-9593245
P.O. Box 586 Yokneam 20692 ISRAEL
 
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openfabrics.org/pipermail/general/attachments/20050110/9d487dbc/attachment.html>