2.6.32.1 kernel unable to use more than 2 of 16 CPUs on Intel E5540 (i7)
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From: Robert Hancock on 24 Jun 2010 20:30 On 06/24/2010 04:05 PM, Roland Dreier wrote: > Your config seems to have CONFIG_PM and therefore CONFIG_ACPI disabled. > So the kernel is relying on mptable information. Unsurprisingly on a > modern system, that info is probably broken -- since everything would > have been tested with ACPI. > > Try turning on CONFIG_ACPI and see if that helps at all. Indeed, not having ACPI enabled will prevent any multi-core CPU detection. ACPI really has to be enabled for any modern x86 system to work properly. I'd think that the CONFIG_ACPI really should be defaulted on more strongly - maybe force it on if CONFIG_EMBEDDED isn't set or something.. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Kurt Newman on 25 Jun 2010 17:50
Roland Dreier wrote: > Your config seems to have CONFIG_PM and therefore CONFIG_ACPI disabled. > So the kernel is relying on mptable information. Unsurprisingly on a > modern system, that info is probably broken -- since everything would > have been tested with ACPI. > > Try turning on CONFIG_ACPI and see if that helps at all. Turning on ACPI solved the problem. I don't understand why ACPI needs to be turned on, but after reading the power management ldp it confirms what you said. I just didn't think that this would have mattered. Thanks for the help, Kurt For anyone else with this problem, here's something to read: Some SMP system manufacturers may have omitted the pre-ACPI tables used for SMP configurations. In this case, ACPI is required. If you have a newer system that supports Hyper-Threading, you will need to enable ACPI (and, of course, SMP). Without it, your Linux system may be unable to discover and initialize all of the virtual processors. IA64 machines require ACPI as well. Additionally, NUMA servers are starting to require it for proper initialization. Source: http://tldp.org/HOWTO/Battery-Powered/powermgm.html#HYPERTHREAD -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |