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Re: Problems with PAE kernel sort of solved.

On Mon, 25 Jul 2011 16:10:37 -0400, Frank McCormick wrote:

> On 25/07/11 01:41 PM, Camaleón wrote:
>> On Mon, 25 Jul 2011 13:17:55 -0400, Frank McCormick wrote:
>>> I have been having problems with the new series of PAE kernels. I
>>> could never get them to boot on my machine (see bug #632734) .
>> What an ugly (hard to debug) bug ;-(
>>> This morning I installed the "new" 3.0.0 kernel, and spent a half hour
>>> changing BIOS settings in an attempt to get it to boot. Nothing worked
>>> until I turned OFF the hyper-threading option. The kernel now boots
>>> fine, but the system does not see it as a dual-core but as  one CPU.
>>> The problem is the system **seems** significantly slower than it
>>> was..a costly trade-off to run the new kernel. I don't see the
>>> connection between the PAE option the kernel now uses (and which my
>>> dual core CPU supports) and hyper-threading. Can anyone enlighten me
>>> ??
>> Mmm... not sure if this will answer your question but as I understand,
>> HT is the hardware part while SMP is the logical/software part you need
>> to "double" your microprocessor. You need from both to get the job done
>> so when you disable HT in BIOS, is the same that if you had installed a
>> non- SMP kernel.
>> Well, sort of :-)
>    Yes, that I guess is why the system now "sees" only one CPU when I
> have a dual core. But I still fail to understand why turning off
> hyper-threading allows the kernel (supposedly who only major change is
> use of the PAE extension) to boot when it wouldn't before. 

Because PAE is disabled?

Something seems seriously broken with your machine and PAE (HT/PAE 
combo), dunno what nor why because your system looks PAE-aware and 
capable :-?

> Anyway I guess I am barking up the wrong tree - the kernel developers
> seem comfortable with their assumption that it's a hardware fault on my
> machine. Could be, or maybe not.

Maybe... not enough data to tell but a BIOS update may help, I would 
check it out, just in case you haven't already done.



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