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Commit 322850af authored by Yinghai Lu's avatar Yinghai Lu Committed by Ingo Molnar
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x86: make amd quad core 8 socket system not be clustered_box, #2 



quad core 8 socket system will have apic id lifting.the apic id range could
be [4, 0x23]. and apic_is_clustered_box will think that need to three clusters
and that is large than 2. So it is treated as clustered_box.

and will get

Marking TSC unstable due to TSCs unsynchronized

even the CPUs have X86_FEATURE_CONSTANT_TSC set.

this patch will check if the cpu is from AMD.

Signed-off-by: default avatarYinghai Lu <yinghai.lu@sun.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 513ad84b

arch/x86/kernel/apic_64.c

+11 −1
Original line number Diff line number Diff line
@@ -1180,9 +1180,19 @@ __cpuinit int apic_is_clustered_box(void) 
{

	int i, clusters, zeros;

	unsigned id;

	u16 *bios_cpu_apicid = x86_bios_cpu_apicid_early_ptr;

	u16 *bios_cpu_apicid;

	DECLARE_BITMAP(clustermap, NUM_APIC_CLUSTERS);



	/*

	 * there is not this kind of box with AMD CPU yet.

	 * Some AMD box with quadcore cpu and 8 sockets apicid

	 * will be [4, 0x23] or [8, 0x27] could be thought to

	 * have three apic_clusters. So go out early.

	 */

	if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD)

		return 0;



	bios_cpu_apicid = x86_bios_cpu_apicid_early_ptr;

	bitmap_zero(clustermap, NUM_APIC_CLUSTERS);



	for (i = 0; i < NR_CPUS; i++) {