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RE: [Xen-ia64-devel] how to make a "smp xen0 config file", thanks

To: "Tristan Gingold" <Tristan.Gingold@xxxxxxxx>, "You, Yongkang" <yongkang.you@xxxxxxxxx>, "Zhang, Jingke" <jingke.zhang@xxxxxxxxx>
Subject: RE: [Xen-ia64-devel] how to make a "smp xen0 config file", thanks
From: "Tian, Kevin" <kevin.tian@xxxxxxxxx>
Date: Tue, 13 Jun 2006 19:08:38 +0800
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Thread-topic: [Xen-ia64-devel] how to make a "smp xen0 config file", thanks
>From: Tristan Gingold
>Sent: 2006年6月13日 17:43
>Le Mardi 13 Juin 2006 10:58, You, Yongkang a écrit :
>> Hi Tristan,
>> That machine disabled HT from BIOS. Xen should also only can see 2,
>why 4?
>> Native Linux hasn't problem run on it.
>You have only one socket, two cores enabled.  Right ?
>I still do not understand why Linux doesn't start the second CPU.  Xen
>to be correct.

The hint should be:

(XEN) ACPI: Local APIC address c0000000fee00000
(XEN) ACPI: [APIC:0x07] ignored 12 entries of 16 found

Currently the default config file sets CONFIG_NR_CPUS to be 4, 
which means only the early 4 entries can be parsed. See Jingke's log:

(XEN) ACPI: LSAPIC (acpi_id[0x00] lsapic_id[0xc0] lsapic_eid[0x18] 
(XEN) CPU 0 (0xc018) enabled (BSP)
(XEN) ACPI: LSAPIC (acpi_id[0x04] lsapic_id[0xc1] lsapic_eid[0x18] 
(XEN) CPU 4 (0xc118) enabled

The 2nd active LSAPIC entry happens to be 5th slot in MADT table, 
which is ignored by dom0. Then it's easy to understand why Tristan 
can succeed on his box due to possibly different LSAPIC entries.

Jingke, could you try enlarging CONFIG_NR_CPUS to be same as 
MAX_VIRT_CPUS, to see whether dom0 smp will be up for you?


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