From mboxrd@z Thu Jan  1 00:00:00 1970
From: Hiroaki SHIMODA <shimoda.hiroaki@gmail.com>
Subject: Re: Strange latency spikes/TX network stalls on Sun Fire X4150(x86)
 and e1000e
Date: Thu, 7 Jun 2012 02:19:37 +0900
Message-ID: <20120607021937.a5638bfd.shimoda.hiroaki@gmail.com>
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Cc: Eric Dumazet <eric.dumazet@gmail.com>,
	Tom Herbert <therbert@google.com>,
	Denys Fedoryshchenko <denys@visp.net.lb>,
	<netdev@vger.kernel.org>, <e1000-devel@lists.sourceforge.net>,
	<jeffrey.t.kirsher@intel.com>, <davem@davemloft.net>
To: Jesse Brandeburg <jesse.brandeburg@intel.com>
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On Wed, 6 Jun 2012 09:26:35 -0700
Jesse Brandeburg <jesse.brandeburg@intel.com> wrote:

> On Wed, 6 Jun 2012 Hiroaki SHIMODA <shimoda.hiroaki@gmail.com> wrote:
> > Sorry for long delay. I'll post.
> > (I have no idea how to fix this problem as keeping TXDCTL.WTHRESH to 5)
> 
> I don't like changing WTHRESH wholesale because making the global change
> to WTHRESH on e1000e just to fix this one bug (likely specific to a
> particular chip/hardware) will adversely effect performance on many
> models supported by e1000e not demonstrating any problem.  We could
> possibly check something in for just ESB2LAN (S5000 chipset).
> 
> Other people (tom herbert) with this same chipset have been unable to
> reproduce this issue right?

I understand your performance concern.

The affected chip would be e1000_82571, e1000_82572, e1000_82574
and e1000_80003es2lan which have FLAG2_DMA_BURST bit in
adapter->flags2.
Anyway, I have no objection intel guys NACK to my patch and
provide right fix. But in that case please consider 82574L chip too
which I observed similar behaviour.

Thanks.