***SPAM*** Re: [ofa-general] Re: [PATCH] mlx4_core: add module parameter to enable/disable QoS support. (for 2.6.27)

[Or Gerlitz]

On Tue, Jul 15, 2008 at 9:41 PM, Roland Dreier <rdreier at cisco.com> wrote:

> thanks, applied... a few comments:
>

Jack, Roland,

I'd be happy to get educated first, why this patch/param is needed at all?
and second, why ofed 1.3 is shipped with this patch/param but an opposite
default value...?

As for the first point, I understand that telling the HCA "don't spend time
on arbitration between VLs" may reduce some ns from the latency, but I don't
think it worth the hassle of managing this module param, with connectx and
PCIe gen2 I recently saw 0.99 us latency (rtt/2) so I guess you can't go
much below that with this patch, or is there another reason for its
existence?

Or.
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