* [PATCH] docs: add vpmu description to xen-command-line.markdown
@ 2012-04-27 9:20 Dietmar Hahn
2012-04-27 9:29 ` Ian Campbell
0 siblings, 1 reply; 4+ messages in thread
From: Dietmar Hahn @ 2012-04-27 9:20 UTC (permalink / raw)
To: xen-devel
# HG changeset patch
# User Dietmar Hahn <dietmar.hahn@ts.fujitsu.com>
# Date 1335517766 -7200
# Node ID 9ba4e4a5f3b1b7dad77e2801afc0253d6d30d565
# Parent 107285938c50f82667bd4d014820b439a077c22c
Add a short description to the vpmu boot option in the
xen-command-line.markdown
Signed-off-by: Dietmar Hahn <dietmar.hahn@ts.fujitsu.com>
diff -r 107285938c50 docs/misc/xen-command-line.markdown
--- a/docs/misc/xen-command-line.markdown Thu Apr 26 10:03:08 2012 +0100
+++ b/docs/misc/xen-command-line.markdown Fri Apr 27 11:09:26 2012 +0200
@@ -543,7 +543,28 @@ console even after dom0 has been started
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
--
Company details: http://ts.fujitsu.com/imprint.html
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] docs: add vpmu description to xen-command-line.markdown
2012-04-27 9:20 [PATCH] docs: add vpmu description to xen-command-line.markdown Dietmar Hahn
@ 2012-04-27 9:29 ` Ian Campbell
2012-04-27 10:00 ` Dietmar Hahn
2012-05-10 17:03 ` Ian Jackson
0 siblings, 2 replies; 4+ messages in thread
From: Ian Campbell @ 2012-04-27 9:29 UTC (permalink / raw)
To: Dietmar Hahn; +Cc: xen-devel
On Fri, 2012-04-27 at 10:20 +0100, Dietmar Hahn wrote:
> # HG changeset patch
> # User Dietmar Hahn <dietmar.hahn@ts.fujitsu.com>
> # Date 1335517766 -7200
> # Node ID 9ba4e4a5f3b1b7dad77e2801afc0253d6d30d565
> # Parent 107285938c50f82667bd4d014820b439a077c22c
>
> Add a short description to the vpmu boot option in the
> xen-command-line.markdown
>
>
> Signed-off-by: Dietmar Hahn <dietmar.hahn@ts.fujitsu.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Can't we just blacklist systems with the nehalem quirk and otherwise
enable it?
Ian.
>
>
> diff -r 107285938c50 docs/misc/xen-command-line.markdown
> --- a/docs/misc/xen-command-line.markdown Thu Apr 26 10:03:08 2012 +0100
> +++ b/docs/misc/xen-command-line.markdown Fri Apr 27 11:09:26 2012 +0200
> @@ -543,7 +543,28 @@ console even after dom0 has been started
> 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
>
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] docs: add vpmu description to xen-command-line.markdown
2012-04-27 9:29 ` Ian Campbell
@ 2012-04-27 10:00 ` Dietmar Hahn
2012-05-10 17:03 ` Ian Jackson
1 sibling, 0 replies; 4+ messages in thread
From: Dietmar Hahn @ 2012-04-27 10:00 UTC (permalink / raw)
To: xen-devel; +Cc: Ian Campbell
Am Freitag 27 April 2012, 10:29:55 schrieb Ian Campbell:
> On Fri, 2012-04-27 at 10:20 +0100, Dietmar Hahn wrote:
> > # HG changeset patch
> > # User Dietmar Hahn <dietmar.hahn@ts.fujitsu.com>
> > # Date 1335517766 -7200
> > # Node ID 9ba4e4a5f3b1b7dad77e2801afc0253d6d30d565
> > # Parent 107285938c50f82667bd4d014820b439a077c22c
> >
> > Add a short description to the vpmu boot option in the
> > xen-command-line.markdown
> >
> >
> > Signed-off-by: Dietmar Hahn <dietmar.hahn@ts.fujitsu.com>
>
> Acked-by: Ian Campbell <ian.campbell@citrix.com>
>
> Can't we just blacklist systems with the nehalem quirk and otherwise
> enable it?
I'm not sure how to create a blacklist. The problem is, the processor models
named in the check_pmc_quirk() function were found be doing some performance
counter tests with machines accessible be me and looking what happens.
As some other models may have the same PMU the hang may occur on other machines
too.
Maybe we can change the policy to switch always on the vpmu stuff for the
AMD cpus and enforce a flag for Intel?
Dietmar.
>
> Ian.
>
> >
> >
> > diff -r 107285938c50 docs/misc/xen-command-line.markdown
> > --- a/docs/misc/xen-command-line.markdown Thu Apr 26 10:03:08 2012 +0100
> > +++ b/docs/misc/xen-command-line.markdown Fri Apr 27 11:09:26 2012 +0200
> > @@ -543,7 +543,28 @@ console even after dom0 has been started
> > 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
--
Company details: http://ts.fujitsu.com/imprint.html
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] docs: add vpmu description to xen-command-line.markdown
2012-04-27 9:29 ` Ian Campbell
2012-04-27 10:00 ` Dietmar Hahn
@ 2012-05-10 17:03 ` Ian Jackson
1 sibling, 0 replies; 4+ messages in thread
From: Ian Jackson @ 2012-05-10 17:03 UTC (permalink / raw)
To: Ian Campbell; +Cc: Dietmar Hahn, xen-devel
Ian Campbell writes ("Re: [Xen-devel] [PATCH] docs: add vpmu description to xen-command-line.markdown"):
> On Fri, 2012-04-27 at 10:20 +0100, Dietmar Hahn wrote:
> > # HG changeset patch
> > # User Dietmar Hahn <dietmar.hahn@ts.fujitsu.com>
> > # Date 1335517766 -7200
> > # Node ID 9ba4e4a5f3b1b7dad77e2801afc0253d6d30d565
> > # Parent 107285938c50f82667bd4d014820b439a077c22c
> >
> > Add a short description to the vpmu boot option in the
> > xen-command-line.markdown
> >
> >
> > Signed-off-by: Dietmar Hahn <dietmar.hahn@ts.fujitsu.com>
>
> Acked-by: Ian Campbell <ian.campbell@citrix.com>
Thanks,
Committed-by: Ian Jackson <ian.jackson@eu.citrix.com>
^ permalink raw reply [flat|nested] 4+ messages in thread
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2012-04-27 9:29 ` Ian Campbell
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2012-05-10 17:03 ` Ian Jackson
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