[ofa-general] maximum IB/iWARP max_inline_data size

[Dotan Barak]

Jeff Squyres wrote:
> If you ibv_create_qp() with max_inline_data==0:
>
> - Mellanox ConnectX reports a number that is a formula based on 
> several values, such as max_send_sge and max_recv_sge.  But its actual 
> max inline value (I think Pasha told me) is 1k.
>
> - Chelsio T3 always reports a fixed value back -- its actual 
> max_inline_data value (64).
>
> - Preliminary tests with NetEffect NE020 seem to show same behavior as 
> T3 (always report back 64).
>
> Our bias in OMPI is to figure such values dynamically at run-time.  
> With T3/NE020, it seems to be easy.  Note that if you choose a 
> max_inline_data value too large, ibv_create_qp will simply fail.  So 
> how can we figure out what the max_inline_data value is for Mellanox 
> adapters at run-time?  (I'd prefer not to repeatedly trying to create 
> a QP with increasing values of max_inline_data until it fails).
Is it  possible to add such a capability to the HCA capabilities 
structure (the high limit which is supported by the device)?

thanks
Dotan