[openib-general] Re: Re: RFC: e2e credits

[Michael S. Tsirkin]

Quoting r. Sean Hefty <mshefty at ichips.intel.com>:
> Subject: Re: [openib-general] Re: Re: RFC: e2e credits
> 
> Michael S. Tsirkin wrote:
> >"Signifies whether the local CA actually implements End-to-End Flow Control
> >(1), or instead always advertises .invalid credits.(0)."
> >and we just take this meaning, with a clarification: "for this connection".
> 
> This sounds reasonable.
> 
> >Anyway, we have two options: removing this field from CM/CMA,
> >and adding it as a low-level driver module option, or adding
> >it to ib_qp_init_attr?
> >
> >In the later case, I think we can avoid ABI breakage by packing this
> >flag in unused space near other flags.
> >
> >Personally, I think the second option is the less disruptive: it moves the
> >policy of using the hardware flow control out to the ULPs, even if I can't 
> >come
> >up with an example where this is useful - there's close to zero overhead 
> >to have
> >it either.
> 
> My personal preference would be to have this policy controlled by the ULPs.
> 
> - Sean

OK. I'll write a patch.


-- 
Michael S. Tsirkin
Staff Engineer, Mellanox Technologies