Re: [Mactel-linux-users] lost one cpu core when upgraded to RHEL 5.5

[cyberdork33 <cyb...@gm...>]

This was a bug in Ubuntu awhile ago, but only affected 5,2 and newer hardware... I am not sure if it was ever resolved or not. Similar sounding issues though.


On Apr 13, 2010, at 1:24 PM, Justin P. mattock wrote:

> On 04/13/2010 07:57 AM, Geoffrey wrote:
>> Geoffrey wrote:
>>> Anyone out there running 64 bit OS on a macbook pro 4,1.  I upgraded
>>> from 32 bit Red Hat EL 5.4 to 64 bit RHEL 5.4, then again to 64 bit RHEL
>>> 5.5, which is actually still in beta.  I don't know if I lost the core
>>> in the 64 bit 5.4 or not.  I see the following from dmesg:
>>> 
>>> SMP: Allowing 2 CPUs, 0 hotplug CPUs
>>> .
>>> .
>>> SMP alternatives: switching to UP code
>>> .
>>> .
>>> SMP motherboard not detected.
>>> .
>>> .
>>> SMP disabled
>> 
>> Thought I'd update the list with a recent success:
>> 
>> For whatever reason, I could not get the initial installation RHEL 5.4
>> disk to even boot until I stumbled across a link that suggested the
>> following boot parms:
>> 
>> acpi=force noapic irqpoll
>> 
>> I don't know why they worked, but they did.  Once installed, I found
>> that I had to add them to my grub.conf to get the install to boot, but
>> all was happy.  After moving to 64bit, I lost one core of my two core
>> processor.  After much discussion with RH, I revisited these parameters
>> and found that by removing the noapic, parm, my macbook would still boot
>> and I got both cores.  The weird thing is, I've tried every combination
>> of these parms before in order to remove them from my boot process in
>> the past, but my macbook would not boot.  There must be something about
>> the latest RHEL 5.5 kernel that resolved that issue.
>> 
>> The weird thing is, I did not have this issue on 32bit RHEL 5.4.  That
>> is, I had both cores using all these parms.
>> 
> 
> this doesn't seem right..
> you need apic etc... they must be
> doing something in there configs somewhere
> (COFNIG_SMP=y if set gives you both cores
> (but could be wrong)).
> 
> Justin P. Mattock
> 
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