From: Len Brown <lenb@kernel.org>
To: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Andi Kleen <andi@firstfloor.org>,
linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org,
Andi Kleen <ak@linux.intel.com>
Subject: Re: [PATCH 4/5] ACPI: Do cpufreq clamping for throttling per package v2
Date: Mon, 13 Feb 2012 18:30:33 -0500 [thread overview]
Message-ID: <4F399D19.9090904@kernel.org> (raw)
In-Reply-To: <20120206163106.GB32061@srcf.ucam.org>
On 02/06/2012 11:31 AM, Matthew Garrett wrote:
> On Mon, Feb 06, 2012 at 08:17:11AM -0800, Andi Kleen wrote:
>> +#define reduction_pctg(cpu) \
>> + per_cpu(cpufreq_thermal_reduction_pctg, phys_package_first_cpu(cpu))
>
> I don't like using percentages here - we end up with the potential for
> several percentages to end up mapping to the same P state.
Does it matter?
> I've sent a
> patch that replaces the percentage code with just stepping through P
> states instead. But otherwise, yes, this seems sensible. An open
> question is whether we should be doing the same on _PPC notifications.
> There's some vague evidence that Windows does.
If you stepped by P-states, then you behave entirely differently
on a machine with many P-states vs a machine with few P-states.
There is code floating about that exposes every 100 MHz step on SNB
and later as a P-state -- you can have quite a few...
thanks,
-Len Brown, Intel Open Source Technology Center
next prev parent reply other threads:[~2012-02-13 23:30 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-06 16:17 Updated throttling fix patchkit Andi Kleen
2012-02-06 16:17 ` [PATCH 1/5] ACPI: ec: Do request_region outside WARN() Andi Kleen
2012-03-22 6:08 ` Len Brown
2012-02-06 16:17 ` [PATCH 2/5] ACPI: Make ACPI interrupt threaded Andi Kleen
2012-02-06 16:17 ` [PATCH 4/5] ACPI: Do cpufreq clamping for throttling per package v2 Andi Kleen
2012-02-06 16:31 ` Matthew Garrett
2012-02-06 17:59 ` Andi Kleen
2012-02-13 23:30 ` Len Brown [this message]
2012-02-14 0:17 ` Matthew Garrett
2012-03-22 6:13 ` Len Brown
2012-03-30 10:05 ` Len Brown
2012-03-30 11:46 ` Matthew Garrett
2012-03-30 12:00 ` Len Brown
2012-02-06 16:17 ` [PATCH 5/5] Disable MCP limit exceeded messages from Intel IPS driver Andi Kleen
2012-02-07 19:45 ` Jesse Barnes
2012-03-22 6:25 ` Len Brown
[not found] ` <1328545032-21373-4-git-send-email-andi@firstfloor.org>
2012-02-06 16:27 ` [PATCH 3/5] ACPI: EC: Add a limited number of repeats after false EC interrupts Matthew Garrett
2012-02-06 18:01 ` Andi Kleen
2012-02-06 16:31 ` Updated throttling fix patchkit Matthew Garrett
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