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authorAndi Kleen <ak@suse.de>2006-02-26 04:18:31 +0100
committerLinus Torvalds <torvalds@g5.osdl.org>2006-02-26 09:53:30 -0800
commit13a229abc25640813f1480c0478dfc6bdbc1c19e (patch)
treebdb9da6ba327bd4f6ee64aa3ca1548670be395f2 /arch/x86_64
parent5342fba5412cead88b61ead07168615dbeba1ee3 (diff)
[PATCH] x86_64: Only do the clustered systems have unsynchronized TSC assumption on IBM systems
Big Unisys systems have multiple clusters too, but they have an synchronized TSC. I'm using the SMBIOS to check for vendor == IBM. Cc: Chris McDermott <lcm@us.ibm.com> Cc: "Protasevich, Natalie" <Natalie.Protasevich@unisys.com> Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/x86_64')
-rw-r--r--arch/x86_64/kernel/apic.c9
1 files changed, 8 insertions, 1 deletions
diff --git a/arch/x86_64/kernel/apic.c b/arch/x86_64/kernel/apic.c
index e5b14c57eaa..d70605eda33 100644
--- a/arch/x86_64/kernel/apic.c
+++ b/arch/x86_64/kernel/apic.c
@@ -962,12 +962,14 @@ void smp_apic_timer_interrupt(struct pt_regs *regs)
irq_exit();
}
+int __initdata unsync_tsc_on_multicluster;
+
/*
* oem_force_hpet_timer -- force HPET mode for some boxes.
*
* Thus far, the major user of this is IBM's Summit2 series:
*
- * Clustered boxes may have unsynced TSC problems if they are
+ * Some clustered boxes may have unsynced TSC problems if they are
* multi-chassis. Use available data to take a good guess.
* If in doubt, go HPET.
*/
@@ -977,6 +979,11 @@ __cpuinit int oem_force_hpet_timer(void)
unsigned id;
DECLARE_BITMAP(clustermap, NUM_APIC_CLUSTERS);
+ /* Only do this check on IBM machines - big Unisys systems
+ use multiple clusters too, but have synchronized TSC */
+ if (!unsync_tsc_on_multicluster)
+ return 0;
+
bitmap_zero(clustermap, NUM_APIC_CLUSTERS);
for (i = 0; i < NR_CPUS; i++) {