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From: Thomas Renninger <trenn@suse.de>
To: linux-pm@lists.linux-foundation.org
Cc: Len Brown <lenb@kernel.org>,
	x86@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [linux-pm] idle-test patches queued for upstream
Date: Thu, 27 May 2010 10:45:33 +0200	[thread overview]
Message-ID: <201005271045.33500.trenn@suse.de> (raw)
In-Reply-To: <1274928151-30919-1-git-send-email-lenb@kernel.org>

On Thursday 27 May 2010 04:42:23 Len Brown wrote:
> Please look over and test this patch set.
> (If you test linux-next, you already have it)
> 
> There are a few simple patches, leading up to a new intel_idle driver.
> 
> Note that you can get the patch series as a single patch here:
> http://ftp.kernel.org/pub/linux/kernel/people/lenb/idle/patches/2.6.34/idle-test-2.6.34.diff.gz
> 
> or pull from this git branch
> git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-idle-2.6.git idle-test
> 
> Both are vs 2.6.34.
> 
> Why is it good to have a native intel_idle driver?
> 
> Basically, we think we can do better than ACPI.
Why exactly? Is there any info missing in the ACPI tables?
Or is this just to be more independent from OEMs?

> Indeed, on my (production level commerically available) Nehalem desktop
> the ACPI tables are broken and an ACPI OS idles at 100W.  With this
> driver the box idles at 85W.
What exactly was broken there?

IMO this is a step backward.
CPUfreq runs rather well on nearly every machine supporting it without
tons of static frequency tables in kernel. Even powernow-k8 might get merged
into acpi-cpufreq.

Intel set up a huge ACPI API for this and now it's not used anymore?!?
Will these parts get obsoleted in a future spec?
While for C-states there are not that many static entries needed, another
drawback could be that OEMs will disable/hide C-states on purpose.

Using ACPI table based C-states by default and using intel_idle.enable=1
or similar for workarounds sounds safer.
At least as long as the driver is experimental.

Does Windows use ACPI C-state info for idle?

Thanks,

   Thomas

  parent reply	other threads:[~2010-05-27  8:44 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-05-27  2:42 Len Brown
2010-05-27  2:42 ` [PATCH 1/8] cpuidle: fail to register if !CONFIG_CPU_IDLE Len Brown
2010-05-27  2:42   ` [PATCH 2/8] cpuidle: add cpuidle_unregister_driver() error check Len Brown
2010-05-27  3:14     ` Andrew Morton
2010-05-27  5:11       ` [PATCH-v2 " Len Brown
2010-05-27  5:13         ` Andrew Morton
2010-05-27  2:42   ` [PATCH 3/8] cpuidle: make cpuidle_curr_driver static Len Brown
2010-05-27  5:27     ` [PATCH-v2 " Len Brown
2010-05-27 18:40       ` Luck, Tony
2010-05-27 23:30         ` Len Brown
2010-05-27  2:42   ` [PATCH 4/8] ACPI: allow a native cpuidle driver to displace ACPI Len Brown
2010-05-27  2:42   ` [PATCH 5/8] sched: clarify commment for TS_POLLING Len Brown
2010-05-27  5:53     ` [PATCH-v2 " Len Brown
2010-05-27  2:42   ` [PATCH 6/8] acpi_pad: uses MONITOR/MWAIT, so it doesn't need to clear TS_POLLING Len Brown
2010-05-27  2:42   ` [PATCH 7/8] ACPI: acpi_idle: touch TS_POLLING only in the non-MWAIT case Len Brown
2010-05-27  2:42   ` [PATCH 8/8] intel_idle: create a native cpuidle driver for select intel processors Len Brown
2010-05-27  3:44     ` Andrew Morton
2010-05-28  3:57       ` Len Brown
2010-05-30  9:20         ` Andi Kleen
2010-05-27  8:53     ` [linux-pm] " Thomas Renninger
2010-05-28  1:44       ` Len Brown
2010-05-28  7:46         ` Thomas Renninger
2010-05-28 17:38           ` Len Brown
2010-05-29  4:17         ` Thomas Renninger
2010-05-27 14:14     ` Kevin Hilman
2010-05-27 14:22       ` Arjan van de Ven
2010-05-27 14:36         ` Kevin Hilman
2010-05-28  0:22           ` Len Brown
2010-05-28 17:28             ` Kevin Hilman
2010-05-27 14:51         ` [linux-pm] " Igor Stoppa
2010-05-28  3:14           ` Arjan van de Ven
2010-05-28 17:27             ` Kevin Hilman
2010-05-29  0:38               ` Arjan van de Ven
2010-05-28  2:32     ` Chase Douglas
2010-05-28  4:16       ` Len Brown
2010-05-28 15:09         ` Chase Douglas
2010-05-28 17:43           ` Len Brown
2010-05-28 19:51             ` Chase Douglas
2010-05-28 20:14               ` Chase Douglas
2010-05-27  5:25   ` (No subject header) Milton Miller
2010-05-27  5:47     ` Len Brown
2010-05-27  8:45 ` Thomas Renninger [this message]
2010-05-28  0:59   ` [linux-pm] idle-test patches queued for upstream Len Brown
2010-05-28  8:07     ` Thomas Renninger
2010-05-28 17:42       ` Len Brown
2010-06-16  7:53     ` Pavel Machek

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