To: linux-kernel@vger.kernel.org
From: Stephen Hemminger <shemminger@osdl.org>
Subject: Re: [openib-general] Re: [PATCH 07/16] ehca: interrupt handling
 routines
Date: Tue, 9 May 2006 12:04:21 -0700
Organization: OSDL
Message-ID: <20060509120421.6ac3f15c@localhost.localdomain>
References: <4450A196.2050901@de.ibm.com>
	<adaejz9o4vh.fsf@cisco.com>
	<445B4DA9.9040601@de.ibm.com>
	<adafyjomsrd.fsf@cisco.com>
	<44608C90.30909@de.ibm.com>
	<adalktbcgl1.fsf@cisco.com>
	<20060509164919.GC5063@mellanox.co.il>
	<40FCD6B6-9135-43C1-8974-E9070475DB78@schihei.de>
Mime-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
NNTP-Posting-Date: Tue, 9 May 2006 19:04:16 +0000 (UTC)
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1070
Lines: 25

On Tue, 9 May 2006 20:57:01 +0200
Heiko J Schick <info@schihei.de> wrote:

> On 09.05.2006, at 18:49, Michael S. Tsirkin wrote:
> 
> >> 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.
> >
> > For RX, isn't this basically what NAPI is doing?
> > Only NAPI seems better, avoiding interrupts completely and avoiding  
> > latency hit
> > by only getting triggered on high load ...
> 
> Does NAPI schedules CQ callbacks to different CPUs or stays the callback
> (handling of data, etc.) on the same CPU where the interrupt came in?
> 

NAPI runs callback on same cpu that called netif_rx_schedule. 
This has benefit of cache location and reduces locking overhead.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/