linux-kernel - Re: [PATCH 1/1] via-rhine: Fix hanging with high CPU load on low-end broads.

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Message-ID: <20111228101710.51c4893f@nehalam.linuxnetplumber.net>
Date:	Wed, 28 Dec 2011 10:17:10 -0800
From:	Stephen Hemminger <shemminger@...tta.com>
To:	Bjarke Istrup Pedersen <gurligebis@...too.org>
Cc:	Ben Hutchings <bhutchings@...arflare.com>,
	linux-kernel@...r.kernel.org, netdev@...r.kernel.org,
	Roger Luethi <rl@...lgate.ch>
Subject: Re: [PATCH 1/1] via-rhine: Fix hanging with high CPU load on
 low-end broads.

Looks like the hardware isn't really disabling interrupts correctly to support
NAPI. NAPI is supposed to be friendly and under load the work should move to
ksoftirqd. I suspect the IRQ management in this driver is borked.
There is some stupid spin loops in the IRQ handler that happen when looking for
Tx IRQ. I would run with debug set  and see if this is triggering.
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