From: Kurt Newman <knewman@globaldataguard.com>
To: Carsten Aulbert <carsten.aulbert@aei.mpg.de>
Cc: linux-admin@vger.kernel.org
Subject: Re: 2.6.32.1 kernel configuration only seeing 1 core on Intel E5540 CPU
Date: Fri, 25 Jun 2010 16:54:01 -0500 [thread overview]
Message-ID: <4C252579.4050101@globaldataguard.com> (raw)
In-Reply-To: <201006240943.38529.carsten.aulbert@aei.mpg.de>
Carsten Aulbert wrote:
> Hi Kurt
>
> On Thursday 24 June 2010 00:53:46 Kurt Newman wrote:
>> I've loaded this same i7 Nehalem machine with CentOS 5.3
>> (2.6.18-128.el5PAE), Ubuntu 9.04 (2.6.28-11-generic), and a modified
>> distro with a custom kernel (2.6.32.1).
>>
>> The CentOS and Ubuntu kernels find all 4 cores just fine; however, my
>> custom kernel only finds 1. I've enabled the following:
>>
>> - SMP
>> - X86_BIGSMP (systems with more than 8 cpus)
>> - X86_EXTENDED_PLATFORM (extended x86 platform)
>> - SCHED_SMT (hyper-threading)
>> - SCHED_MC (Multi-core scheduler)
>> - and varied between M686 (Pentium Pro) and MCORE2 (newer Xeon)
>
> Just guessing, but could the CentOS and Ubuntu Kernel be a 64bit variant,
> while your custom one is 32bit? (also .1 is heavily outdated .15 is the
> current which apparently fixes several bugs).
>
> I've not been using 32bit kernel for a couple of years and never with a multi-
> core system thus just poking into the dark here.
Just to follow up. The solution was that I needed to enable Power
Management and ACPI. Apparently newer machines require it (e.g.
hyper-threading or IA64).
Read http://tldp.org/HOWTO/Battery-Powered/powermgm.html#HYPERTHREAD for
more information.
prev parent reply other threads:[~2010-06-25 21:54 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-06-23 22:53 2.6.32.1 kernel configuration only seeing 1 core on Intel E5540 CPU Kurt Newman
2010-06-24 7:43 ` Carsten Aulbert
2010-06-24 13:39 ` S. Kurt Newman
2010-06-25 21:54 ` Kurt Newman [this message]
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