From: Simon Horman <horms@kernel•org>
To: Przemek Kitszel <przemyslaw.kitszel@intel•com>
Cc: intel-wired-lan@lists•osuosl.org, netdev@vger•kernel.org,
Tony Nguyen <anthony.l.nguyen@intel•com>,
lukasz.czapnik@intel•com, Jacob Keller <jacob.e.keller@intel•com>,
Alexander Lobakin <aleksander.lobakin@intel•com>,
Nebojsa Stevanovic <nebojsa.stevanovic@gcore•com>,
Christian Rohmann <christian.rohmann@inovex•de>
Subject: Re: [PATCH iwl-net] ice: fix stats being updated by way too large values
Date: Wed, 28 Feb 2024 10:12:18 +0000 [thread overview]
Message-ID: <20240228101218.GB292522@kernel.org> (raw)
In-Reply-To: <20240227143124.21015-1-przemyslaw.kitszel@intel.com>
On Tue, Feb 27, 2024 at 03:31:06PM +0100, Przemek Kitszel wrote:
> Simplify stats accumulation logic to fix the case where we don't take
> previous stat value into account, we should always respect it.
>
> Main netdev stats of our PF (Tx/Rx packets/bytes) were reported orders of
> magnitude too big during OpenStack reconfiguration events, possibly other
> reconfiguration cases too.
>
> The regression was reported to be between 6.1 and 6.2, so I was almost
> certain that on of the two "preserve stats over reset" commits were the
> culprit. While reading the code, it was found that in some cases we will
> increase the stats by arbitrarily large number (thanks to ignoring "-prev"
> part of condition, after zeroing it).
>
> Note that this fixes also the case where we were around limits of u64, but
> that was not the regression reported.
>
> Full disclosure: I remember suggesting this particular piece of code to
> Ben a few years ago, so blame on me.
>
> Fixes: 2fd5e433cd26 ("ice: Accumulate HW and Netdev statistics over reset")
> Reported-by: Nebojsa Stevanovic <nebojsa.stevanovic@gcore•com>
> Link: https://lore.kernel.org/intel-wired-lan/VI1PR02MB439744DEDAA7B59B9A2833FE912EA@VI1PR02MB4397.eurprd02.prod.outlook.com
> Reported-by: Christian Rohmann <christian.rohmann@inovex•de>
> Link: https://lore.kernel.org/intel-wired-lan/f38a6ca4-af05-48b1-a3e6-17ef2054e525@inovex.de
> Reviewed-by: Jacob Keller <jacob.e.keller@intel•com>
> Signed-off-by: Przemek Kitszel <przemyslaw.kitszel@intel•com>
Reviewed-by: Simon Horman <horms@kernel•org>
next prev parent reply other threads:[~2024-02-28 10:12 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-27 14:31 [PATCH iwl-net] ice: fix stats being updated by way too large values Przemek Kitszel
2024-02-28 10:12 ` Simon Horman [this message]
2024-03-06 12:42 ` [Intel-wired-lan] " Pucha, HimasekharX Reddy
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