linux-kernel - Re: [RFC patch] reset TSC at the begining of check_tsc

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Date:	Tue, 2 Jun 2009 15:05:44 +0800
From:	Luming Yu <luming.yu@...il.com>
To:	Frans Pop <elendil@...net.nl>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: [RFC patch] reset TSC at the begining of check_tsc_warp

On Tue, Jun 2, 2009 at 7:10 AM, Frans Pop <elendil@...net.nl> wrote:
> Luming Yu wrote:
>> Without this patch, we always get kernel warning that TSC warp between
>> CPUs, and TSC is marked unstable due to check_tsc_sync_source failed if
>> the CPUs have the problem of not-synced initial TSC.
>>
>> It hurts CPUs with constant-tsc feature, but with unsynced initial TSC
>> value...
>>
>> The downside is we could break perfect synced TSC with this patch.
>> Please review, test and apply.
>
> I've tested this on my desktop (working TSC) and my laptop (non-working TSC).
> On both machines the patch didn't make any difference.

Thanks for testing, but if there was no warnings like
"Measured 439164 cycles TSC warp between CPUs, turning off TSC clock."
the patch won't help....

--Luming
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