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From: Segher Boessenkool <segher@kernel.crashing.org>
Subject: Re: [openib-general] [PATCH 07/16] ehca: interrupt handling routines
Date: Wed, 10 May 2006 01:35:57 +0200
To: Roland Dreier <rdreier@cisco.com>
Cc: linux-kernel@vger.kernel.org, openib-general@openib.org,
	linuxppc-dev@ozlabs.org, Christoph Raisch <RAISCH@de.ibm.com>,
	Hoang-Nam Nguyen <HNGUYEN@de.ibm.com>, Marcus Eder <MEDER@de.ibm.com>
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>     Heiko> Yes, I agree. It would not be an optimal solution, because
>     Heiko> other upper level protocols (e.g. SDP, SRP, etc.) or
>     Heiko> userspace verbs would not be affected by this
>     Heiko> changes. Nevertheless, how can an improved "scaling" or
>     Heiko> "SMP" version of IPoIB look like. How could it be
>     Heiko> implemented?
>
> The trivial way to do it would be to use the same idea as the current
> ehca driver: just create a thread for receive CQ events and a thread
> for send CQ events, and defer CQ polling into those two threads.
>
> Something even better may be possible by specializing to IPoIB of  
> course.

The hardware IRQ should go to some CPU close to the hardware itself.   
The
softirq (or whatever else) should go to the same CPU that is handling  
the
user-level task for that message.  Or a CPU close to it, at least.


Segher