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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: Ravikiran Thirumalai <kiran@scalex86.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Ravikiran G Thirumalai 2008-03-20 00:45:08 -07:00 committed by Ingo Molnar
parent 9f6d8552a9
commit 1cb68487f5
1 changed files with 7 additions and 1 deletions
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8
arch/x86/kernel/apic_64.c
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@ -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