Messages in this thread Patch in this message | | | Subject | [PATCH: x86] Print the hypervisor returned tsc_khz during boot. | From | Alok Kataria <> | Date | Sun, 23 Aug 2009 18:08:23 -0700 |
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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 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 hypervisor returned. Please consider for tip.
-- Signed-off-by: Alok N Kataria <akataria@vmware.com>
Index: linux-tip-master/arch/x86/kernel/tsc.c =================================================================== --- linux-tip-master.orig/arch/x86/kernel/tsc.c 2009-08-23 17:53:44.000000000 -0700 +++ linux-tip-master/arch/x86/kernel/tsc.c 2009-08-23 17:55:08.000000000 -0700 @@ -405,7 +405,10 @@ unsigned long native_calibrate_tsc(void) hv_tsc_khz = get_hypervisor_tsc_freq(); if (hv_tsc_khz) { - printk(KERN_INFO "TSC: Frequency read from the hypervisor\n"); + printk(KERN_INFO "TSC: Frequency read from the hypervisor : " + "%lu.%03lu MHz\n", + (unsigned long) hv_tsc_khz / 1000, + (unsigned long) hv_tsc_khz % 1000); return hv_tsc_khz; }
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