[ofa-general] Re: [PATCH 1/5] IB/ipoib: Split CQs for IPOIB UD

[Shirley Ma]

On Fri, 2008-02-01 at 15:40 +0200, Eli Cohen wrote:
> IB/ipoib: Split CQs for IPOIB UD
> 
> This comes as a preparation for using unsignalled QP in UD mode. It
> uses a dedicated CQ for the UD send. The CQ is not armed and is polled
> for completion right after sending a packet.
> This patch and the following patches fix bugs 760 and 761.
> 
> Signed-off-by: Eli Cohen <eli at mellanox.co.il>

I filed a patch back two years ago to split CQ. The feedback was it
didn't benefit mthca since it had only one interrupt shared between send
and recv. More context switches were generated when splitting CQ. Then I
decided to wait the multiple interrupt vector to be implemented in
device driver layer to push this patch later with multiple interrupt
vectors (This is the next item on my list). The why the performance got
improved without multiple interrupt support here?

Thanks
Shirley