linux-kernel - Fwd: [PATCH RFC] x86: hpet: Avoid the readback penalty

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Message-ID: <AANLkTi=1SyZe=G1DCPcccnRRsTtqYow-0-92PPqWq=jE@mail.gmail.com>
Date:	Thu, 16 Sep 2010 00:45:09 -0400
From:	John Drescher <drescherjm@...il.com>
To:	LKML <linux-kernel@...r.kernel.org>
Subject: Fwd: [PATCH RFC] x86: hpet: Avoid the readback penalty

On Wed, Sep 15, 2010 at 9:54 AM, John Drescher <drescherjm@...il.com> wrote:
> On Wed, Sep 15, 2010 at 9:11 AM, Thomas Gleixner <tglx@...utronix.de> wrote:
>> On Tue, 14 Sep 2010, tip-bot for Thomas Gleixner wrote:
>>> x86: hpet: Work around hardware stupidity
>>
>> After my brain recovered from yesterdays exposure with the x86 timer
>> horror, I came up with a different solution for this problem, which
>> avoids the readback of the compare register completely. It works
>> nicely on my affected ATI system, but needs some exposure to the other
>> machines.
>>
>> Comments ?
>>
>
> I can test this on my i7 machine in tonight (around 12 hours from now).

Seems to work fine on my i7 box. I applied the first patch to
2.6.36-rc4-git2 then after that I applied the new patch from this
email. Both patches applied cleanly and I am now running the patched
kernel without any issue. I turned off the clocksource=acpi_pm
workaround I had enabled from the original problem.

jmd1 ~ # uname -a
Linux jmd1 2.6.36-rc4-git2-no-penalty #3 SMP PREEMPT Wed Sep 15
21:25:53 EDT 2010 x86_64 Intel(R) Core(TM) i7 CPU 920 @ 2.67GHz
GenuineIntel GNU/Linux

John



-- 
John M. Drescher
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