From f9adab4cc952b64433afdec151f84cc05f5168ee Mon Sep 17 00:00:00 2001 From: Dietmar Hahn Date: Fri, 27 Apr 2012 11:09:26 +0200 Subject: docs: add vpmu description to xen-command-line.markdown Add a short description to the vpmu boot option in the xen-command-line.markdown Signed-off-by: Dietmar Hahn Committed-by: Ian Jackson Acked-by: Ian Campbell --- docs/misc/xen-command-line.markdown | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) (limited to 'docs/misc/xen-command-line.markdown') 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 -- cgit v1.2.3