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Date: Thu, 19 Jan 2012 15:18:13 +0200
From: Tudor Laurentiu <Laurentiu.Tudor@freescale.com>
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To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Subject: Re: [PATCH] powerpc/booke64: Configurable lazy interrupt disabling
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Hi Ben,

On 01/18/2012 11:10 PM, Benjamin Herrenschmidt wrote:
> On Wed, 2012-01-18 at 16:35 +0200, Laurentiu Tudor wrote:
>> This patch adds a menuconfig option that allows controlling
>> the lazy interrupt disabling feature implemented by this
>> commit:
>>
>> commit d04c56f73c30a5e593202ecfcf25ed43d42363a2
>> Author: Paul Mackerras
>> Date:   Wed Oct 4 16:47:49 2006 +1000
>>
>>      [POWERPC] Lazy interrupt disabling for 64-bit machines
>>
>> The code in 'powerpc/include/asm/hw_irq.h' was rearranged and
>> cleaned-up a bit in order to reduce the number of needed #ifdef's.
>
> It's still nasty.

Yep, there is still room for improvement. Perhaps trimming some of those 
various interrupt enable/disable functions & macros. However I don't 
think I have enough experience to do this ... so, any suggestions are 
welcomed.

> Do you have numbers showing that it's worth disabling
> on BookE ?

On fsl's p5020 there should be some performance gains because disabling 
"lazy ee" allows enabling the "external proxy" feature.
The thing is I can't prove this because I have no idea what benchmark to 
run. Let me know if you guys know of any relevant benchmark I could try.

---
Best Regards, Laurentiu