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Message-ID: <D12839161ADD3A4B8DA63D1A134D084026E4953A04@ESGSCCMS0001.eapac.ericsson.se>
Date: Fri, 15 Apr 2011 10:10:54 +0800
From: Wei Gu <wei.gu@...csson.com>
To: Eric Dumazet <eric.dumazet@...il.com>,
Peter Zijlstra <a.p.zijlstra@...llo.nl>
CC: Alexander Duyck <alexander.h.duyck@...el.com>,
netdev <netdev@...r.kernel.org>,
"Kirsher, Jeffrey T" <jeffrey.t.kirsher@...el.com>,
Mike Galbraith <efault@....de>
Subject: RE: Low performance Intel 10GE NIC (3.2.10) on 2.6.38 Kernel
Hi Eric,
I tried another parameter intel_idle.max_cstate=0 with 2.6.35.3
Looks like this setting make the a little better, less rx_error and much more stable.
However I haven't found this kernel param in the kernel document, but supprise it still works somehow:)
I will check with the HP guys to see if I need to do extra configuration in BIOS to disable more ACPI related features on DL580.
Thanks
WeiGu
-----Original Message-----
From: Eric Dumazet [mailto:eric.dumazet@...il.com]
Sent: Friday, April 15, 2011 12:57 AM
To: Peter Zijlstra
Cc: Alexander Duyck; Wei Gu; netdev; Kirsher, Jeffrey T; Mike Galbraith
Subject: Re: Low performance Intel 10GE NIC (3.2.10) on 2.6.38 Kernel
Le jeudi 14 avril 2011 à 18:56 +0200, Peter Zijlstra a écrit :
> 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.
>
>
>
Normally, Wei Gu already asked to not use C states.
http://h20000.www2.hp.com/bc/docs/support/SupportManual/c01804533/c01804533.pdf
How can we/he check this ?
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