[Openib-windows] RE: IBDM and IBMgtSim Proposal Comments

[Fab Tillier]

> From: Hal Rosenstock [mailto:halr at voltaire.com]
> Sent: Thursday, July 07, 2005 2:05 PM
> 
> On Thu, 2005-07-07 at 16:43, Fab Tillier wrote:
> > umad is the lowest level API in Linux, but not in Windows.  So either the
> > diagnostics interface to the lowest level layer (umad for Linux, IBAL for
> > Windows), or the diagnostics interface to some higher abstraction layer.
> > If a higher abstraction layer, why not use the existing OSM vendor layer
> > and skip porting umad to Windows all together?
> 
> In Linux, OSM vendor layer is implemented on top of umad. Whether it is
> a higher abstraction layer is another matter. It is an abstraction with
> different semantics and may be higher as I am not sure whether the umad
> and mad libraries could be put on top of the OSM vendor layer but the
> other way 'round works.

Since OSMV works over umad, IBAL, Gen1 and so forth, to me that makes it a
higher level abstraction.  I'm not here to debate which is higher - I don't
care.  I was just making the point that if the argument for interfacing to umad
in Linux is that it is the lowest level interface possible, that same argument
should be made for Windows.  Consistency in logic what I'm asking for here.

> 
> I looked at IBAL some time ago but can't comment now on how it compares.
> 
> So it appears there are 3 choices:
> 1. Port OpenIB Linux libraries to Windows and OpenIB Linux "diags" port
> as well (second part is less work than next alternative)
> 2. Port OpenIB Linux diagnostics to OSM vendor layer
> 3. No OpenIB "Linux" diagnostics in the windows environment

What about:
4. Port OpenIB Linux "diags" to Windows/IBAL.

Seems like a pretty obvious choice, and what I've been talking about in my
previous emails.

I don't care about OSMV - I care about the access layer in Windows.  The
functionality for user-level MAD clients is already there - why not use it?  If
there are problems with the exiting MAD interface, let's address them.  If that
ends up making the interface more similar to the Linux umad interface, so be it.

However, I'm not in favor of just porting umad to Windows because someone
randomly decreed that it is *the* user-mode MAD interface for the industry.  It
isn't.  umad in Linux is the functional equivalent of IBAL in Windows, period.

- Fab