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Re: RFC: NAPI packet weighting patch

To: Mitch Williams <mitch.a.williams@xxxxxxxxx>
Subject: Re: RFC: NAPI packet weighting patch
From: Stephen Hemminger <shemminger@xxxxxxxx>
Date: Fri, 27 May 2005 14:01:32 -0700
Cc: netdev@xxxxxxxxxxx, hadi@xxxxxxxxxx, Robert.Olsson@xxxxxxxxxxx, "Ronciak, John" <john.ronciak@xxxxxxxxx>, "Venkatesan, Ganesh" <ganesh.venkatesan@xxxxxxxxx>, "Brandeburg, Jesse" <jesse.brandeburg@xxxxxxxxx>
In-reply-to: <Pine.CYG.4.58.0505271305590.2148@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
Organization: Open Source Development Lab
References: <Pine.CYG.4.58.0505261406210.2364@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx> <20050527085055.79da3d75@xxxxxxxxxxxxxxxxx> <Pine.CYG.4.58.0505271305590.2148@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
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On Fri, 27 May 2005 13:27:04 -0700
Mitch Williams <mitch.a.williams@xxxxxxxxx> wrote:

> 
> Stephen, Robert, and Jamal all replied to my original message, and all
> said approximately the same thing:  "Why don't you just reduce the weight
> in the driver?  It does the same thing."
> 
> To which I reply, respectfully, I know that.  And no it doesn't, not
> exactly.
> 
> My primary reason for adding this setting is to allow for runtime tweaking
> -- just like max_backlog has right now.  Driver weight is a compile-time
> setting, and has to be changed for every driver that you run.
> 
> This setting allows you to scale the weight of all your drivers, at
> runtime, in one place.  It's complimentary to Stephen's max_weight idea --
> his patch affects how long you spend in any individual softirq; my patch
> affects how long you spend in any driver's individual NAPI poll routine,
> as well as how long the softirq lasts.
>

Why not just allow adjusting dev->weight via sysfs?
        

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