* Alok Kataria <[email protected]> wrote:
> 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 <[email protected]>
>
> 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;
> }
Makes sense. Note, arch/x86/kernel/tsc.c changed recently so this
patch does not apply anymore - mind merging it on top of that and
re-send it?
Thanks,
Ingo
<snip>...
> Makes sense. Note, arch/x86/kernel/tsc.c changed recently so this
> patch does not apply anymore - mind merging it on top of that and
> re-send it?
Sure, here is the one which fits on top of current tip.
I also added a print statement for the case where the TSC frequecy
cannot be read from vmware's hypervisor.
Thanks.
--
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. Please consider for tip.
---
Signed-off-by: Alok N Kataria <[email protected]>
Index: linux-x86-tree.git/arch/x86/kernel/cpu/vmware.c
===================================================================
--- linux-x86-tree.git.orig/arch/x86/kernel/cpu/vmware.c 2009-09-04 12:59:45.000000000 -0700
+++ linux-x86-tree.git/arch/x86/kernel/cpu/vmware.c 2009-09-04 13:01:41.000000000 -0700
@@ -58,6 +58,9 @@ static unsigned long vmware_get_tsc_khz(
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");
}
/*
Commit-ID: 6399c087458859cddff2d6b46befb95b866df3e0
Gitweb: http://git.kernel.org/tip/6399c087458859cddff2d6b46befb95b866df3e0
Author: Alok Kataria <[email protected]>
AuthorDate: Fri, 4 Sep 2009 13:13:39 -0700
Committer: Ingo Molnar <[email protected]>
CommitDate: Sun, 20 Sep 2009 20:25:36 +0200
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 <[email protected]>
LKML-Reference: <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
---
arch/x86/kernel/cpu/vmware.c | 6 ++++++
1 files changed, 6 insertions(+), 0 deletions(-)
diff --git a/arch/x86/kernel/cpu/vmware.c b/arch/x86/kernel/cpu/vmware.c
index 0a46b4d..1cbed97 100644
--- a/arch/x86/kernel/cpu/vmware.c
+++ b/arch/x86/kernel/cpu/vmware.c
@@ -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");
}
/*