Commit 6399c087 authored Sep 04, 2009 by Alok Kataria Committed by Ingo Molnar Sep 20, 2009

x86: Print the hypervisor returned tsc_khz during boot



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>

parent bfefb7a0

arch/x86/kernel/cpu/vmware.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -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");
		}

		/*