From: ykzhao <yakui.zhao@intel.com>
To: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: "lenb@kernel.org" <lenb@kernel.org>,
"linux-acpi@vger.kernel.org" <linux-acpi@vger.kernel.org>,
Venkatesh Pallipadi <venki@google.com>
Subject: Re: [PATCH] ACPI: Fix the incorrect calculation about C-state idle time
Date: Thu, 03 Jun 2010 09:06:54 +0800 [thread overview]
Message-ID: <1275527214.3718.38.camel@localhost.localdomain> (raw)
In-Reply-To: <20100602150659.GA5335@srcf.ucam.org>
On Wed, 2010-06-02 at 23:06 +0800, Matthew Garrett wrote:
> On Wed, Jun 02, 2010 at 11:04:09AM +0800, yakui.zhao@intel.com wrote:
> > From: Zhao Yakui <yakui.zhao@intel.com>
> >
> > The C-state idle time is not calculated correctly, which will return the wrong
> > residency time in C-state. It will have the following effects:
> > 1. The system can't choose the deeper C-state when it is idle next time.
> > Of course the system power is increased. E.g. On one server machine about 40W
> > idle power is increased.
> > 2. The powertop shows that it will stay in C0 running state about 95% time
> > although the system is idle at most time.
>
> What kind of system was this seen on?
This can be seen on laptops. But maybe the idle power effect is not
significant on laptops like that on server machine.
I also test the power on one T400 laptop and test shows that about
0.3W idle power is increased.
thanks.
Yakui
>
next prev parent reply other threads:[~2010-06-03 1:09 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-06-02 3:04 [PATCH] ACPI: Fix the incorrect calculation about C-state idle time yakui.zhao
2010-06-02 15:06 ` Matthew Garrett
2010-06-03 1:06 ` ykzhao [this message]
2010-06-03 1:39 ` Matthew Garrett
2010-06-02 16:28 ` Venkatesh Pallipadi
2010-06-03 5:42 ` Len Brown
2010-06-02 16:29 ` Venkatesh Pallipadi
2010-06-04 7:35 ` Len Brown
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