netdev - Re: [PATCH] bnx2x: fix occasional statistics off-by-4GB error

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Message-ID: <1363549074.4752.3.camel@lb-tlvb-eilong.il.broadcom.com>
Date:	Sun, 17 Mar 2013 21:37:54 +0200
From:	"Eilon Greenstein" <eilong@...adcom.com>
To:	"David Miller" <davem@...emloft.net>
cc:	dmitry@...adcom.com, zenczykowski@...il.com, maze@...gle.com,
	netdev@...r.kernel.org, yuvalmin@...adcom.com
Subject: Re: [PATCH] bnx2x: fix occasional statistics off-by-4GB error

On Sun, 2013-03-17 at 14:24 -0400, David Miller wrote:
> From: "Dmitry Kravkov" <dmitry@...adcom.com>
> Date: Sun, 17 Mar 2013 13:10:37 +0000
> 
> > Probably this commit resolved the issue:
> > 
> > commit bef05406ac0ea6f468e1e25e9934f3011ea9259b
> > Author: Dmitry Kravkov <dmitry@...adcom.com>
> > Date:   Tue Sep 11 04:34:08 2012 +0000
> > 
> >     bnx2x: Avoid sending multiple statistics queries
> > 
> > Can you try it pls?
> 
> These are completely seperate bugs.
> 
> The macro in question does not handle rollover of the lower 32-bits of
> the statistic properly at all, and therefore Maciej's patch should be
> applied and queud up for -stable.
> 
> Please give it your ACK unless you can find a bug in his change.

Both the high value and the low value are read from the chip - so this
patch will increment the higher 32 bits twice (well, more than once).
Not taking the HW/FW high counter at all is also not acceptable since
the reading frequency is not high enough without those.

So the original patch is nacked, but we are trying to figure out what is
causing the statistics to misbehave and it might be related to sending
statistics query twice.

Thanks,
Eilon


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