netdev - Re: [patch 09/11] forcedeth: improve NAPI logic

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Date:	Fri, 27 Apr 2007 08:27:10 -0400
From:	Jeff Garzik <jeff@...zik.org>
To:	Ayaz Abdulla <aabdulla@...dia.com>
CC:	akpm@...ux-foundation.org, netdev@...r.kernel.org, mingo@...e.hu
Subject: Re: [patch 09/11] forcedeth: improve NAPI logic

Ayaz Abdulla wrote:
> 
> 
> Jeff Garzik wrote:
>> Ayaz Abdulla wrote:
>>
>>> I don't see why the NAPI handler needs to process tx packets. The ISR 
>>> will handle all tx processing.
>>
>>
>> It is a design choice, not a requirement.
>>
>> Moving non-RX interrupt processing to the NAPI handler can help as 
>> loads increase.  The basic idea is to do as much work as possible in 
>> the NAPI handler with NIC interrupts masked.  That mitigates global 
>> system per-interrupt overhead even more than an only-RX NAPI scheme.
>>
>> Several net drivers do TX completion handling in the NAPI handler.
> 
> Ok. In that case, the patch needs to be improved.
> 
> The following needs to be done when NAPI is enabled:
> - remove the tx handling within the ISRs
> - mask off the tx interrupts within the ISRs that handle tx processing
> - re-enable tx interrupts within the NAPI handler
> - add tx handling within the NAPI handler (this patch covers it)

Agreed.

	Jeff



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