Re: [kvm-devel] Guest kernel hangs in smp kvm for older kernels priorto tsc sync cleanup

From: Avi Kivity
Date: Wed Dec 19 2007 - 10:41:29 EST


Glauber de Oliveira Costa wrote:
Changes in rate does not sound good. It's possibly what's screwing up
my paravirt clock implementation in smp.

You should renew the timebase on vcpu migration, and hook cpufreq so that changes in frequency are reflected in the timebase.

Since the host updates guest time prior to putting vcpu to run, two
vcpus that start running at different times will have different system
values.

Now if the vcpu that started running later probes the time first,
we'll se the time going backwards. A constant tsc rate is the only way
around
my limited mind sees around the problem (besides, obviously, _not_
making the system time per-vcpu).

I tried disabling frequency scaling (rmmod acpi_cpufreq) but that didn't help my present problems.

--
error compiling committee.c: too many arguments to function

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