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>
Index: linux.git.trees/arch/x86/kernel/apic_64.c
===================================================================
--- linux.git.trees.orig/arch/x86/kernel/apic_64.c 2008-03-19 20:42:28.187659497 -0700
+++ linux.git.trees/arch/x86/kernel/apic_64.c 2008-03-19 21:24:17.705515003 -0700
@@ -1208,7 +1208,7 @@ __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;
@@ -1248,6 +1248,12 @@ __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
--
