Change default cpufreq governor to ondemand

Back in c/s 18950 the default cpufreq governor was set to userspace (it had previously been performance). However, since there is no supplied userspace program or script that will change the frequency this is at best a no-op. Worse, on some hardware with some BIOS revisions, this actually sets the CPUs running at their lowest frequency rather than their highest and there is a corresponding (and initially puzzling) drop in performance.

This patch changes the default governor to "ondemand" which should make it the same as the Linux default and will provide power savings for the majority without needing to write a userspace governor. For those that want to install their own governor, that is still possible.

diff -r 88d2273c3942 xen/include/acpi/cpufreq/cpufreq.h
@@ -100,7 +100,7 @@
 extern int cpufreq_register_governor(struct cpufreq_governor *governor);
 extern int cpufreq_unregister_governor(struct cpufreq_governor *governor);
 extern struct cpufreq_governor *__find_governor(const char *governor);
-#define CPUFREQ_DEFAULT_GOVERNOR &cpufreq_gov_userspace
+#define CPUFREQ_DEFAULT_GOVERNOR &cpufreq_gov_dbs;
 
 /* pass a target to the cpufreq driver */
 extern int __cpufreq_driver_target(struct cpufreq_policy *policy,

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Thanks for fixing the typo, Kier.

jch