-----Original Message-----
From: gshan [mailto:gshan@alcatel-lucent.com] 
Sent: Thursday, December 24, 2009 5:16 PM
To: michael@ellerman.id.au
Cc: Kumar Gopalpet-B05799; netdev@vger.kernel.org; 
linuxppc-dev@lists.ozlabs.org
Subject: Re: [HELP] BAD interrupts

Michael Ellerman wrote:

quoted

On Wed, 2009-12-23 at 19:41 +0530, Kumar Gopalpet-B05799 wrote:
  

quoted

Hi all,
 
I am trying linux 2.6.32-rc3 in SMP mode. I am seeing a lot of BAD 
interrupts when I do a "cat  /proc/interrupts".
 
I am running a forwarding application b/w two ethernet ports 
(ethernet uses gianfar driver).
 
Has any one observed these BAD interrupts ? If so, can someone help 
me in understanding why these interrupts come and how to 

resolve it ?

quoted

quoted

You'll need to tell us what platform you're running on.

The BAD interrupts come from ppc_spurious_interrupts. It's a 

count of 

quoted

the number of times we entered do_IRQ() (ie. took an external 
interrupt), but when we asked the interrupt controller which irq it 
was, the interrupt controller said there was no irq.

Depending on your interrupt controller that might happen 

sometimes for 

quoted

valid reasons. Or it might indicate something is setup wrong.

cheers
  

I think it will help to show us your /proc/interrupts so that 
how you suffered from bad interrupts.

I am running linux-2.6.29 in SMP mode on P2020RDB ( ruuning at
1200/600/667). The test scenario forwarding 
application and is a bidirectioanl flow between eth0 & eth2.

Attached is the complete log of the test scenario.

I also noted another observation that when all the interrupts are mapped
to a single core, the BAD interrupts stop coming.

--

Thanks
Sandeep