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Subject[PATCH 2/2] xen/cpufreq: Disable the cpu frequency scaling drivers from loading.
By using the functionality provided by "[CPUFREQ]: provide
disable_cpuidle() function to disable the API."

Under the Xen hypervisor we do not want the initial domain to exercise
the cpufreq scaling drivers. This is b/c the Xen hypervisor is
in charge of doing this as well and we can end up with both the
Linux kernel and the hypervisor trying to change the P-states
leading to weird performance issues.

Signed-off-by: Konrad Rzeszutek Wilk <>
arch/x86/xen/setup.c | 1 +
1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index e03c636..4461e0a 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -420,6 +420,7 @@ void __init xen_arch_setup(void)
boot_cpu_data.hlt_works_ok = 1;
+ disable_cpufreq();
boot_option_idle_override = IDLE_HALT;

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