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From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Alexander Duyck <alexander.h.duyck@intel.com>
Cc: Wei Gu <wei.gu@ericsson.com>,
	Eric Dumazet <eric.dumazet@gmail.com>,
	netdev <netdev@vger.kernel.org>,
	"Kirsher, Jeffrey T" <jeffrey.t.kirsher@intel.com>,
	Mike Galbraith <efault@gmx.de>
Subject: Re: Low performance Intel 10GE NIC (3.2.10) on 2.6.38 Kernel
Date: Thu, 14 Apr 2011 18:56:42 +0200	[thread overview]
Message-ID: <1302800202.2035.32.camel@laptop> (raw)
In-Reply-To: <4DA723F1.7000901@intel.com>

On Thu, 2011-04-14 at 09:42 -0700, Alexander Duyck wrote:

> I'm doing some more digging into this now.  One thought that occurred to 
> me is that if the patch you mention is having some sort of effect this 
> could be a sign of perhaps a kernel timer or scheduling problem.

Right, so the removal of the NO_HZ throttle will allow the CPU to go
into C states more often, this could result in longer wake-up times for
IRQs.

We reverted because:
  - it caused significant battery drain due to not going into C states
    often enough, and
  - its a much better idea to implement these things in the idle
    governor since it already has the job of guestimating the idle
    duration.

I really can't remember back far enough to even come up with a theory of
why kernels prior to merging the NO_HZ throttle would not exhibit this
problem.




  parent reply	other threads:[~2011-04-14 16:54 UTC|newest]

Thread overview: 58+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <D12839161ADD3A4B8DA63D1A134D084026E48B9BEB@ESGSCCMS0001.eapac.ericsson.se>
2011-04-07  4:58 ` Question on "net: allocate skbs on local node" Eric Dumazet
2011-04-07  5:16   ` Eric Dumazet
2011-04-07  6:16     ` Eric Dumazet
2011-04-07  7:22       ` Low performance Intel 10GE NIC (3.2.10) on 2.6.38 Kernel Wei Gu
2011-04-07  8:07         ` Eric Dumazet
2011-04-07  8:39           ` Wei Gu
2011-04-07  9:06             ` Eric Dumazet
2011-04-07 11:15               ` Wei Gu
2011-04-07 11:46                 ` Eric Dumazet
2011-04-07 13:41                   ` Eric Dumazet
2011-04-07 15:58                   ` Alexander Duyck
2011-04-07 16:03                     ` Eric Dumazet
2011-04-07 16:20                       ` Alexander Duyck
2011-04-07 16:37                         ` Eric Dumazet
2011-04-08  8:59                         ` Wei Gu
2011-04-08  9:07                           ` Eric Dumazet
2011-04-08  9:15                             ` Wei Gu
2011-04-08  9:49                               ` Eric Dumazet
2011-04-08  9:59                                 ` Wei Gu
2011-04-08  9:41                             ` Wei Gu
2011-04-08 12:19                             ` Wei Gu
2011-04-08 12:56                               ` Eric Dumazet
2011-04-08 14:10                                 ` Wei Gu
2011-04-08 14:49                                   ` Stephen Hemminger
2011-04-09  3:51                                     ` Wei Gu
2011-04-08 15:07                                   ` Eric Dumazet
2011-04-09  3:27                                     ` Wei Gu
2011-04-09  6:36                                       ` Eric Dumazet
2011-04-10  7:02                                         ` Wei Gu
2011-04-11 14:50                                           ` Alexander Duyck
2011-04-11 15:00                                             ` Wei Gu
2011-04-11 15:14                                             ` Wei Gu
2011-04-11 15:42                                               ` Eric Dumazet
2011-04-12  1:22                                                 ` Wei Gu
2011-04-12  4:40                                                 ` Wei Gu
2011-04-12  4:56                                                   ` Eric Dumazet
2011-04-12  5:18                                                     ` Wei Gu
2011-04-14  5:42                                                 ` Wei Gu
2011-04-14  6:07                                                   ` Eric Dumazet
2011-04-14  6:33                                                     ` Eric Dumazet
2011-04-14  6:58                                                       ` Wei Gu
2011-04-14 16:42                                                         ` Alexander Duyck
2011-04-14 16:45                                                           ` Eric Dumazet
2011-04-14 16:56                                                           ` Peter Zijlstra [this message]
2011-04-14 16:57                                                             ` Eric Dumazet
2011-04-14 17:49                                                               ` Eric Dumazet
2011-04-14 19:08                                                                 ` Alexander Duyck
2011-04-15  2:10                                                               ` Wei Gu
2011-04-15  8:57                                                               ` Peter Zijlstra
2011-04-15  9:14                                                                 ` Wei Gu
2011-04-18 21:12                                                                   ` Jesse Brandeburg
2011-04-19  4:09                                                                     ` Wei Gu
2011-04-21  2:57                                                                     ` Wei Gu
2011-04-21  3:25                                                                     ` Wei Gu
2011-04-08 16:22                               ` Alexander Duyck
2011-04-09  3:36                                 ` Wei Gu
2011-04-09  4:40                                   ` Alexander H Duyck
2011-04-09  6:12                                     ` Wei Gu

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