[ofw] RE: [PATCH] ib_qp_create_t

[Reuven Amitai]

see comment below.
 
________________________________

From: Fab Tillier [mailto:ftillier at windows.microsoft.com] 
Sent: Wednesday, March 26, 2008 10:08 AM
To: Reuven Amitai; ofw at lists.openfabrics.org
Subject: RE: [PATCH] ib_qp_create_t



Can the HCA set it to more than requested?  Or is it only allowed to set
it to less? 

[Reuven] I was wrong.The call will fails if the value exceed the HCA
limit ( just like max WR\SGE ).

             The HCA may set it more than the requested value.

             In order to know the real value one should query qp.


Having the HCA set it to less introduces a different behavior than the
rest of the QP creation parameters, where the call fails if the value is
too big (max WR, max SGE, etc).  Requiring a call to query in order to
find out whether the requested inline data was granted seems a bit
cumbersome.

 

-Fab

 

From: Reuven Amitai [mailto:reuven at mellanox.co.il] 
Sent: Wednesday, March 26, 2008 1:06 AM
To: Fab Tillier; ofw at lists.openfabrics.org
Subject: RE: [PATCH] ib_qp_create_t

 

Max inline is input from the user to the HCA but the HCA may set it less
than the user request (due to HCA limitations).

I don't think there is one optimal value for max_inline in every
situation that HW can set if the user want to use inline data.

ib_qp_create_t is only input and the user should query the qp in order
to get the real value of max inline.

 

Reuven.

 

________________________________

From: Fab Tillier [mailto:ftillier at windows.microsoft.com] 
Sent: Wednesday, March 26, 2008 9:32 AM
To: Reuven Amitai; ofw at lists.openfabrics.org
Subject: RE: [PATCH] ib_qp_create_t

Should max inline be an input or an output?  The optimal size of inline
data is something the HW knows, not the consumer.  So perhaps it would
make sense for the consumer to indicate that they want to use inline
data, and then the HCA driver to return the amount of inline data
available?

 

-Fab

 

From: ofw-bounces at lists.openfabrics.org
[mailto:ofw-bounces at lists.openfabrics.org] On Behalf Of Reuven Amitai
Sent: Wednesday, March 26, 2008 12:30 AM
To: ofw at lists.openfabrics.org
Subject: [ofw] [PATCH] ib_qp_create_t

 

Hi,

 

The patch add sq_max_inline member to ib_qp_create_t structure in order
to enable setting max_inline 

(currently, there is no way to guarantee max inline size in qp creation
directly)

we'll need to increase all the relevant interfaces' versions in the next
release (because ib_qp_create_t is contained in IOCTL structure(s))

 

Reuven

 

Index: hw/mthca/user/mlnx_ual_qp.c

===================================================================

--- hw/mthca/user/mlnx_ual_qp.c     (revision 992)

+++ hw/mthca/user/mlnx_ual_qp.c     (working copy)

@@ -120,7 +120,7 @@

      attr.cap.max_recv_wr          = p_create_attr->rq_depth;

      attr.cap.max_send_sge         = p_create_attr->sq_sge;

      attr.cap.max_recv_sge         = p_create_attr->rq_sge;

-     attr.cap.max_inline_data      = 0;              /* absent in IBAL
*/

+     attr.cap.max_inline_data      = p_create_attr->sq_max_inline;

      attr.qp_type                                          =
p_create_attr->qp_type;

      attr.sq_sig_all                                 =
p_create_attr->sq_signaled;

      

Index: inc/iba/ib_types.h

===================================================================

--- inc/iba/ib_types.h  (revision 992)

+++ inc/iba/ib_types.h  (working copy)

@@ -9755,6 +9755,7 @@

 {

      ib_qp_type_t                  qp_type;

 

+     uint32_t                      sq_max_inline;

      uint32_t                      sq_depth;

      uint32_t                      rq_depth;

      uint32_t                      sq_sge;

@@ -9772,6 +9773,10 @@

 *    type

 *          Specifies the type of queue pair to create.

 *

+*    sq_max_inline

+*          Maximum payload that can be inlined directly in a WQE,
eliminating

+*          protection checks and additional DMA operations.

+*

 *    sq_depth

 *          Indicates the requested maximum number of work requests that
may be

 *          outstanding on the queue pair's send queue.  This value must
be less

 

 

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