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Date: Thu, 4 Oct 2001 08:35:02 +0200 (CEST)
From: Ingo Molnar <mingo@elte.hu>
Reply-To: <mingo@elte.hu>
To: jamal <hadi@cyberus.ca>
Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>, <linux-kernel@vger.kernel.org>,
        Robert Olsson <Robert.Olsson@data.slu.se>, <bcrl@redhat.com>,
        <netdev@oss.sgi.com>, Linus Torvalds <torvalds@transmeta.com>,
        Alan Cox <alan@lxorguk.ukuu.org.uk>
Subject: Re: [announce] [patch] limiting IRQ load, irq-rewrite-2.4.11-B5
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On Wed, 3 Oct 2001, jamal wrote:

> > i'm worried by the dev->quota variable a bit. As visible now in the
> > 2.4.10-poll.pat and tulip-NAPI-010910.tar.gz code, it keeps calling the
> > ->poll() function until dev->quota is gone. I think it should only keep
> > calling the function until the rx ring is fully processed - and it should
> > re-enable the receiver afterwards, when exiting net_rx_action.
>
> This would result in an unfairness. Think of one device which receives
> packets really fast that it takes most of the CPU capacity just
> processing it.

no, i asked something else.

i'm asking the following thing. dev->quota, as i read the patch now, can
cause extra calls to ->poll() even though the RX ring of that particular
device is empty and the driver has indicated it's done processing RX
packets. (i'm now assuming that the extra-polling-for-a-jiffy line in the
current patch is removed - that one is a showstopper to begin with.) Is
this claim of mine correct?

	Ingo

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