[ofw] choice between IBAL and winverbs

[Sivaselvam Narayanasamy]

Stan,

Prasanna's question may be :  From a kernel mode driver,  which is the
preferred route, to talk to the layers below :-

a) through the winverbs.sys driver ( available in WinOF 2.1 )  or
b) through the IBAL kernel driver

?

Thanks
Siva
  -----Original Message-----
  From: ofw-bounces at lists.openfabrics.org
[mailto:ofw-bounces at lists.openfabrics.org]On Behalf Of Smith, Stan
  Sent: Tuesday, July 21, 2009 10:52 PM
  To: Prasanna Vv; ofw at lists.openfabrics.org
  Subject: RE: [ofw] choice between IBAL and winverbs



----------------------------------------------------------------------------
--
  From: ofw-bounces at lists.openfabrics.org
[mailto:ofw-bounces at lists.openfabrics.org] On Behalf Of Prasanna Vv
  Sent: Tuesday, July 21, 2009 10:16 AM
  To: ofw at lists.openfabrics.org
  Subject: Re: [ofw] choice between IBAL and winverbs


  Thanks Stan.
  For kernel mode IB  interface,  whether  winverbs-driver IOCTL can be used
or IBAL is the only choice?

  Unfortunately I was not clear w.r.t. user-mode or kernel mode POV
(Point-Of-View).
  A kernel mode implementation of winverbs is not available today. The work
is being discussed and will be available in the WinOF 2.2 release (late
Q4'09/Q1'10).
  Kernel mode winverbs will not be available in the upcoming WinOF 2.1
release.

  stan.

  Regards,
  Prasanna

  Smith, Stan wrote:
Prasanna Vv wrote:
  Hello All,

In WINOF 2.1, most of the ULPs are based on Winverbs, while IPoIB
driver continues to use IBAL .

Actually most of the ULPs are based on IBAL for historical reasons.
It's only newer DAPL providers (Socket-CM & rdma-CM) plus OFED diags which
are using OFED compatibility (aka libibverbs/winverbs).
NetworkDirect continues to use the IBAL IF although there is
work-in-progress to switch over to winverbs to take advantage of overlapped
I/O ops.

  I wish to know if OFED will continue to support and enhance IBAL as
complimentary approach for Winverbs for IB verbs interface ?  Or IBAL
may be phased out ?

The IBAL interface will be supported well into the future, measured in
years.
Under the covers, how the IBAL interface is implemented may change such that
an IBAL function could transparently become a wrapper for a call into
winverbs.
The 'BIG" deal with IBAL is how it implements PNP and how IPoIB and drivers
rely on this implementation.
There are no current plans to change all drivers and IPoIB to use Microsoft
PNP and remove this functionality from IBAL; although it would be an
excellent idea (very large task). For the PNP reasons, IBAL will stick
around for some time.

For future development, I would recommend the OFED compatibility layer
(libibverbs/winverbs).

Stan.

  Thanks,
Prasanna

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