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From: Eric Dumazet <eric.dumazet@gmail.com>
To: Jesper Dangaard Brouer <hawk@comx.dk>
Cc: "David S. Miller" <davem@davemloft.net>,
	netdev@vger.kernel.org,
	Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Subject: Re: [net-next PATCH] igb: update adapter stats when reading /proc/net/dev.
Date: Tue, 05 Oct 2010 23:01:19 +0200	[thread overview]
Message-ID: <1286312479.2593.35.camel@edumazet-laptop> (raw)
In-Reply-To: <1286291947.2796.387.camel@edumazet-laptop>

Le mardi 05 octobre 2010 à 17:19 +0200, Eric Dumazet a écrit :
> Le mardi 05 octobre 2010 à 16:53 +0200, Jesper Dangaard Brouer a écrit :
> 
> > Its already racy, because "ethtool -S" reads out the stats immediately,
> > and thus races with the timer.
> > 
> > See: igb_ethtool.c
> >  igb_get_ethtool_stats() invoke igb_update_stats(adapter);
> > 
> 
> You would be surprised how many bugs are waiting to be found and
> fixed ;)
> 
> 

I took a look at igb stats, and it appears they also are racy on 32bit
arches. igb uses u64 counters, with no synchronization between
producers(writers) and consumers(readers).

Some fixes are needed ;)




  reply	other threads:[~2010-10-05 21:01 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-10-05 14:18 [net-next PATCH] igb: update adapter stats when reading /proc/net/dev Jesper Dangaard Brouer
2010-10-05 14:41 ` Eric Dumazet
2010-10-05 14:53   ` Jesper Dangaard Brouer
2010-10-05 15:19     ` Eric Dumazet
2010-10-05 21:01       ` Eric Dumazet [this message]
2010-10-05 21:16         ` Jesper Dangaard Brouer
2010-10-05 22:34           ` Jeff Kirsher
2010-10-06  3:28             ` Eric Dumazet
2010-10-06  4:36               ` [PATCH net-next] igb: fix stats handling Eric Dumazet
2010-10-06  5:49                 ` Jeff Kirsher
2010-10-06 11:36                 ` Jesper Dangaard Brouer
2010-10-09 23:57                 ` Tantilov, Emil S
2010-10-10  8:14                   ` [PATCH net-next V2] " Eric Dumazet
2010-10-12  0:12                     ` Jeff Kirsher
2010-10-06  5:47               ` [net-next PATCH] igb: update adapter stats when reading /proc/net/dev Jeff Kirsher
2010-10-07  6:36 ` David Miller
2010-10-07  6:44   ` Eric Dumazet
2010-10-07  6:46     ` David Miller
2010-10-07 10:06       ` Jesper Dangaard Brouer
2010-10-07 10:24         ` Eric Dumazet
2010-10-07 11:36           ` Jesper Dangaard Brouer
  -- strict thread matches above, loose matches on Subject: below --
2010-01-12 13:41 Jesper Dangaard Brouer
2010-01-14  1:30 ` David Miller
2010-01-14  3:01   ` Jeff Kirsher

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