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Re: [announce] [patch] limiting IRQ load, irq-rewrite-2.4.11-B5

To: Ingo Molnar <mingo@xxxxxxx>
Subject: Re: [announce] [patch] limiting IRQ load, irq-rewrite-2.4.11-B5
From: jamal <hadi@xxxxxxxxxx>
Date: Wed, 3 Oct 2001 20:46:45 -0400 (EDT)
Cc: <linux-kernel@xxxxxxxxxxxxxxx>, Alexey Kuznetsov <kuznet@xxxxxxxxxxxxx>, Robert Olsson <Robert.Olsson@xxxxxxxxxxx>, Benjamin LaHaise <bcrl@xxxxxxxxxx>, <netdev@xxxxxxxxxxx>, Linus Torvalds <torvalds@xxxxxxxxxxxxx>, Alan Cox <alan@xxxxxxxxxxxxxxxxxxx>
In-reply-to: <Pine.LNX.4.33.0110031828060.8633-100000@xxxxxxxxxxxxxxxxxxxxx>
Sender: owner-netdev@xxxxxxxxxxx

On Wed, 3 Oct 2001, Ingo Molnar wrote:

>
> On Wed, 3 Oct 2001, jamal wrote:
>
> (and the only thing i pointed out was that the patch as-is did not limit
> the amount of polling done.)

you mean in the softirq or the one line in the driver?

>
> > > *if* you can make polling a success in ~90% of the time we enter
> > > tulip_poll() under non-specific server load (ie. not routing), then i
> > > think you have really good metrics.
> >
> > we can make it 100% successful; i mentioned that we only do work, if
> > there is work to be done.
>
> can you really make it 100% successful for rx? Ie. do you only ever call
> the ->poll() function if there is a new packet waiting? How do you know
> with a 100% probability that someone on the network just sent a new packet
> waiting? (without receiving an interrupt to begin with that is.)
>

Take a look at what i think is the NAPI state machine pending a nod
from Alexey and Robert:
http://www.cyberus.ca/~hadi/NAPI-SM.ps.gz

cheers,
jamal



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