[openib-general] IBDM and IBMgtSim Proposal Comments

[Fab Tillier]

> From: Yaron Haviv [mailto:yaronh at voltaire.com]
> Sent: Thursday, July 07, 2005 2:09 PM
> 
> > -----Original Message-----
> > From: openib-general-bounces at openib.org [mailto:openib-general-
> > bounces at openib.org] On Behalf Of Fab Tillier
> > Sent: Thursday, July 07, 2005 11:37 PM
> >
> > > From: Hal Rosenstock [mailto:halr at voltaire.com]
> > > Sent: Thursday, July 07, 2005 10:56 AM
> > >
> > > In the OpenIB architecture, umad is the lowest layer library and the
> > > diagnostics are built on that.
> >
> > That's only true in the *Linux* OpenIB Architecture.  Windows is
> > different - the access layer already provides support for user-level
> > MAD clients, and the API is very close (if not identical) to the
> > IBAL interface OpenSM was originally written to.
> 
> From my understanding the main advantage for using the OSM Vendor
> specific layer is that it is also present in Windows ?

OSMV already exists over a variety of transports, as Eitan mentioned.  It is one
option for developing portable MAD-based tools and diagnostics.

> or does it have some other advantage over the umad layer (from Hal's
> response seems like umad has better layering/functionality) ?

I'm not familiar with it, so I can't answer what functional advantage it has.  I
would expect that as an abstraction layer, it will hide some of the
functionality in umad, just like it likely hides functionality in IBAL.  That's
the price of using a higher level abstraction.  Hal seems to be making the
argument that the lowest layer is the best to use for Linux, but somehow not for
Windows.  I'm just questioning the inconsistency, independent of OSMV.

> If that is the case than you can also suggest to replace the OpenIB
> verbs layer or CM, etc' with the IBAL one because its present in Windows

No, that wasn't the point.  The point was that we have CM, verbs, MAD and so
forth support in Linux and Windows, independent of OSMV, and more importantly
independent of one another.  Just like I'm not suggesting moving the Windows
code to Linux, I'm pushing back against gratuitously moving Linux code to
Windows.  If there's a reason to do it, great.  If it's just because the Linux
code works, I'll be one of the first to point out that the Windows code works
too.

> I believe if we want to do a major change in the management
> infrastructure that is live and kicking (can probably improve like
> always)
> We need a much better reason than "its done this way in Windows"

Turn your above statement around: "I believe if we want to do a major change in
the management infrastructure that is live and kicking (can probably improve
like always) we need a much better reason than "its done this way in Linux"

We're not talking about changing the umad interface in Linux.  Eitan is
proposing having all diagnostics interface to OSVM to facilitate portability.
Hal is proposing porting umad to Windows.  I'm saying just use IBAL - it's
already there and works.

- Fab