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

[Geoffrey <li...@se...>]

Justin P. mattock wrote:
> On 04/14/2010 06:49 AM, Geoffrey wrote:
>> 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
> 
> the acpi=force seems harmless, but the noapic scares me(you need this),
> In any case you should be able to bootup without any of these boot 
> params which makes me wonder if this is a kernel issue and/or userspace

I've played a bit more with this.  Removed the acpi=force too.  Booted 
fine.  Problem if I remove the irqpoll.  System starts to boot, but 
panics on smartd ????  Keyboard is still responsive, ie toggle shift key 
led on/off, but no screen output and can not switch virtual terminals.

Put it back in for now, seems it might have something to do with the 
dvd/cdrom drive.

> 
>>>>
>>>> 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)).
>>
>> No telling, all I know is I have a happy dual core system again with a
>> 64 bit OS. ;)
>>
> 
> That's good news.. if you can, maybe try loading the latest kernel from 
> git, then if the system can bootup without any of these boot params
> then you know there's a regression in the kernel somewhere(then if you 
> have the time do a bisect, and report it to lkml, so there aware of the 
> commit that causes this).

I do hope to do this in the future, just that I've always had a problem 
getting the kernel to boot once I built it.  Need some time to research 
this issue.

> 
> Justin P. Mattock
> 
> 


-- 
Until later, Geoffrey

"I predict future happiness for America if they can prevent
the government from wasting the labors of the people under
the pretense of taking care of them."
- Thomas Jefferson