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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.

Acked-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
[v2: Fix compile error spotted by Benjamin Schweikert <b.schweikert@googlemail.com>]
hifive-unleashed-5.1
Konrad Rzeszutek Wilk 2012-03-13 20:06:57 -04:00
parent 448c8b1d07
commit 48cdd8287f
1 changed files with 2 additions and 0 deletions
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2
arch/x86/xen/setup.c
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@ -10,6 +10,7 @@
#include <linux/pm.h>
#include <linux/memblock.h>
#include <linux/cpuidle.h>
#include <linux/cpufreq.h>
#include <asm/elf.h>
#include <asm/vdso.h>
@ -420,6 +421,7 @@ void __init xen_arch_setup(void)
boot_cpu_data.hlt_works_ok = 1;
#endif
disable_cpuidle();
disable_cpufreq();
WARN_ON(set_pm_idle_to_default());
fiddle_vdso();
}