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x86: Use dmi check in apic_is_clustered() on 64-bit to mark the TSC unstable 

We will have systems with 2 and more sockets 8cores/2thread,
but we treat them as multi chassis - while they could have
a stable TSC domain.

Use DMI check instead.

[ Impact: do not turn possibly stable TSCs off incorrectly ]

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Ravikiran Thirumalai <kiran@scalex86.org>
LKML-Reference: <49F5532A.5000802@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Yinghai Lu 2009-04-26 23:39:38 -07:00 committed by Ingo Molnar
parent b2ba83ff4f
commit e0e42142ba
1 changed files with 59 additions and 27 deletions
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86
arch/x86/kernel/apic/apic.c
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@ -2138,31 +2138,14 @@ static void apic_pm_activate(void) { }
#endif /* CONFIG_PM */
#ifdef CONFIG_X86_64
/*
* apic_is_clustered_box() -- Check if we can expect good TSC
*
* Thus far, the major user of this is IBM's Summit2 series:
*
* 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.
*/
__cpuinit int apic_is_clustered_box(void)
static int __cpuinit apic_cluster_num(void)
{
int i, clusters, zeros;
unsigned id;
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
* vsmp box still need checking...
*/
if ((boot_cpu_data.x86_vendor == X86_VENDOR_AMD) && !is_vsmp_box())
return 0;
bios_cpu_apicid = early_per_cpu_ptr(x86_bios_cpu_apicid);
bitmap_zero(clustermap, NUM_APIC_CLUSTERS);
@ -2198,18 +2181,67 @@ __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 clusters;
}
static int __cpuinitdata multi_checked;
static int __cpuinitdata multi;
static int __cpuinit set_multi(const struct dmi_system_id *d)
{
if (multi)
return 0;
printk(KERN_INFO "APIC: %s detected, Multi Chassis\n", d->ident);
multi = 1;
return 0;
}
static const __cpuinitconst struct dmi_system_id multi_dmi_table[] = {
{
.callback = set_multi,
.ident = "IBM System Summit2",
.matches = {
DMI_MATCH(DMI_SYS_VENDOR, "IBM"),
DMI_MATCH(DMI_PRODUCT_NAME, "Summit2"),
},
},
{}
};
static void __cpuinit dmi_check_multi(void)
{
if (multi_checked)
return;
dmi_check_system(multi_dmi_table);
multi_checked = 1;
}
/*
* apic_is_clustered_box() -- Check if we can expect good TSC
*
* Thus far, the major user of this is IBM's Summit2 series:
* Clustered boxes may have unsynced TSC problems if they are
* multi-chassis.
* Use DMI to check them
*/
__cpuinit int apic_is_clustered_box(void)
{
dmi_check_multi();
if (multi)
return 1;
if (!is_vsmp_box())
return 0;
/*
* If clusters > 2, then should be multi-chassis.
* May have to revisit this when multi-core + hyperthreaded CPUs come
* out, but AFAIK this will work even for them.
* ScaleMP vSMPowered boxes have one cluster per board and TSCs are
* not guaranteed to be synced between boards
*/
return (clusters > 2);
if (apic_cluster_num() > 1)
return 1;
return 0;
}
#endif