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| -rw-r--r-- | docs/misc/xen-command-line.markdown | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/docs/misc/xen-command-line.markdown b/docs/misc/xen-command-line.markdown index a6195f207e..1f3faaa6de 100644 --- a/docs/misc/xen-command-line.markdown +++ b/docs/misc/xen-command-line.markdown @@ -543,7 +543,28 @@ console even after dom0 has been started. The default behaviour is to relinquish control to dom0. ### vpid + ### vpmu +> `= ( bts )` + +> Default: `off` + +Switch on the virtualized performance monitoring unit for HVM guests. + +If the current cpu isn't supported a message like +'VPMU: Initialization failed. ...' +is printed on the hypervisor serial log. + +For some Intel Nehalem processors a quirk handling exist for an unknown +wrong behaviour (see handle_pmc_quirk()). + +If 'vpmu=bts' is specified the virtualisation of the Branch Trace Store (BTS) +feature is switched on on Intel processors supporting this feature. + +*Warning:* +As the BTS virtualisation is not 100% safe and because of the nehalem quirk +don't use the vpmu flag on production systems with Intel cpus! + ### vti\_vhpt\_size ### vti\_vtlb\_size ### watchdog |