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x86: Print the hypervisor returned tsc_khz during boot

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On an AMD-64 system the processor frequency that is printed during
system boot, may be different than the tsc frequency that was
returned by the hypervisor, due to the value returned from
calibrate_cpu.

For debugging timekeeping or other related issues it might be
better to get the tsc_khz value returned by the hypervisor.

The patch below now prints the tsc frequency that the VMware
hypervisor returned.

Signed-off-by: Alok N Kataria <akataria@vmware.com>
LKML-Reference: <1252095219.12518.13.camel@ank32.eng.vmware.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Alok Kataria 2009-09-04 13:13:39 -07:00 committed by Ingo Molnar
parent bfefb7a0c6
commit 6399c08745
1 changed files with 6 additions and 0 deletions
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6
arch/x86/kernel/cpu/vmware.c
View File

@ -58,6 +58,9 @@ static unsigned long vmware_get_tsc_khz(void)
tsc_hz = eax | (((uint64_t)ebx) << 32);
do_div(tsc_hz, 1000);
BUG_ON(tsc_hz >> 32);
printk(KERN_INFO "TSC freq read from hypervisor : %lu.%03lu MHz\n",
(unsigned long) tsc_hz / 1000,
(unsigned long) tsc_hz % 1000);
return tsc_hz;
}
@ -69,6 +72,9 @@ void __init vmware_platform_setup(void)
if (ebx != UINT_MAX)
x86_platform.calibrate_tsc = vmware_get_tsc_khz;
else
printk(KERN_WARNING
"Failed to get TSC freq from the hypervisor\n");
}
/*