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Subject: Re: power increase issue on light load
From: "Alex,Shi" <alex.shi@intel.com>
To: Nikhil Rao <ncrao@google.com>
Cc: Ming Lei <tom.leiming@gmail.com>,
        "peterz@infradead.org" <peterz@infradead.org>,
        "mingo@elte.hu" <mingo@elte.hu>, "Chen, Tim C" <tim.c.chen@intel.com>,
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Date: Mon, 04 Jul 2011 08:45:27 +0800
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On Sat, 2011-07-02 at 02:00 +0800, Nikhil Rao wrote:
> Hi Ming,
> 
> On Thu, Jun 30, 2011 at 10:44 PM, Ming Lei <tom.leiming@gmail.com> wrote:
> > Hi,
> >
> > On Thu, Jun 23, 2011 at 10:43 AM, Alex,Shi <alex.shi@intel.com> wrote:
> >> commit c8b281161dfa4bb5d5be63fb036ce19347b88c63 causes light load
> >> benchmark use more than 10% system power on platform NHM-EP and laptop
> >> Thinkpad T410 etc. The benchmarks are specpower and bltk office.
> >>
> >> I tried to track this issue, but only find deep C sate time reduced
> >> much, about from 90% to 30~40%, the C0 or C1 state increase much on
> >> different machines.
> >>
> >> Powertop just hints RES interrupts has a bit more. but when I try "perf
> >> probe native_smp_send_reschedule". I didn't find much.
> >
> > I see the problem on -rc5 in my T410 too, the fan has been ringing always
> > and powertop reports "Wakeups-from-idle per second : 508.6".
> >
> 
> Thanks for reporting this issue. Looks like the increased resolution
> has a negative impact on power savings balance. I'm looking into this
> issue based on Alex's data, but If you can give a trace or something
> that I can work with it will be really helpful.

Ops, I didn't aware that my evolution didn't send out the trace code to
you, until this e-mail. I just resend them and it should be OK this
time. Please check it and give me a response. 
Thanks!

> 
> -Thanks,
> Nikhil