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Commit 1cb68487 authored by Ravikiran G Thirumalai's avatar Ravikiran G Thirumalai Committed by Ingo Molnar
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x86: apic_is_clustered_box to indicate unsynched TSC's on multiboard vSMP systems 



Indicate TSCs are unreliable as time sources if the platform is
a multi chassi ScaleMP vSMPowered machine.

Signed-off-by: default avatarRavikiran Thirumalai <kiran@scalex86.org>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 9f6d8552

arch/x86/kernel/apic_64.c

+7 −1
Original line number Diff line number Diff line
@@ -1209,7 +1209,7 @@ __cpuinit int apic_is_clustered_box(void) 
	 * will be [4, 0x23] or [8, 0x27] could be thought to

	 * vsmp box still need checking...

	 */

	if (!is_vsmp_box() && (boot_cpu_data.x86_vendor == X86_VENDOR_AMD))

	if ((boot_cpu_data.x86_vendor == X86_VENDOR_AMD) && !is_vsmp_box())

		return 0;



	bios_cpu_apicid = x86_bios_cpu_apicid_early_ptr;
@@ -1249,6 +1249,12 @@ __cpuinit int apic_is_clustered_box(void) 
			++zeros;

	}



	/* ScaleMP vSMPowered boxes have one cluster per board and TSCs are

	 * not guaranteed to be synced between boards

	 */

	if (is_vsmp_box() && clusters > 1)

		return 1;



	/*

	 * If clusters > 2, then should be multi-chassis.

	 * May have to revisit this when multi-core + hyperthreaded CPUs come