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xen-devel
[Xen-devel] RE: TSC scaling and softtsc reprise, and PROPOSAL
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To: |
Keir Fraser <keir.fraser@xxxxxxxxxxxxx>, Ian Pratt <Ian.Pratt@xxxxxxxxxxxxx>, "Zhang, Xiantao" <xiantao.zhang@xxxxxxxxx>, "Xen-Devel (E-mail)" <xen-devel@xxxxxxxxxxxxxxxxxxx> |
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Subject: |
[Xen-devel] RE: TSC scaling and softtsc reprise, and PROPOSAL |
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From: |
Dan Magenheimer <dan.magenheimer@xxxxxxxxxx> |
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Date: |
Thu, 23 Jul 2009 09:45:29 -0700 (PDT) |
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Cc: |
"Dong, Eddie" <eddie.dong@xxxxxxxxx>, John Levon <levon@xxxxxxxxxxxxxxxxx> |
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Thu, 23 Jul 2009 09:51:26 -0700 |
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<C68E4433.10450%keir.fraser@xxxxxxxxxxxxx> |
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> >> pre-VT it wasn't possible to trap RDTSC, so this can't
> help PV guests.
> >
> > For PV guests, CR4.TSD would always be set, generating
> > a general protection fault for every rdtsc. (Or perhaps
> > I am missing some x86 architectural subtlety? This is
> > how it is done on ia64.)
>
> Forgot about CR4.TSD. Of course it's not going to be a super
> fast path,
> since #GP(0) will need to be demuxed by decoding the faulting
> instruction in
> the hypervisor, via a not-so-short path.
And demuxing/decoding can never be "fast enough"?
Even if this particular situation is special-cased?
I'm not saying it will be pretty, or maintainable,
just wondering what the best possible could be?
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- [Xen-devel] RE: TSC scaling and softtsc reprise, and PROPOSAL, (continued)
- [Xen-devel] RE: TSC scaling and softtsc reprise, and PROPOSAL, Dan Magenheimer
- [Xen-devel] RE: TSC scaling and softtsc reprise, and PROPOSAL, Zhang, Xiantao
- [Xen-devel] RE: TSC scaling and softtsc reprise, and PROPOSAL, Dan Magenheimer
- [Xen-devel] RE: TSC scaling and softtsc reprise, and PROPOSAL, Ian Pratt
- [Xen-devel] RE: TSC scaling and softtsc reprise, and PROPOSAL, Dan Magenheimer
- [Xen-devel] Re: TSC scaling and softtsc reprise, and PROPOSAL, Keir Fraser
- [Xen-devel] RE: TSC scaling and softtsc reprise, and PROPOSAL, Dan Magenheimer
- [Xen-devel] Re: TSC scaling and softtsc reprise, and PROPOSAL, Keir Fraser
- [Xen-devel] RE: TSC scaling and softtsc reprise, and PROPOSAL, Dan Magenheimer
- [Xen-devel] Re: TSC scaling and softtsc reprise, and PROPOSAL, Keir Fraser
- [Xen-devel] RE: TSC scaling and softtsc reprise, and PROPOSAL,
Dan Magenheimer <=
- [Xen-devel] RE: TSC scaling and softtsc reprise, and PROPOSAL, Dan Magenheimer
- [Xen-devel] Re: TSC scaling and softtsc reprise, and PROPOSAL, Keir Fraser
- [Xen-devel] RE: TSC scaling and softtsc reprise, and PROPOSAL, Dan Magenheimer
- [Xen-devel] Re: TSC scaling and softtsc reprise, and PROPOSAL, Keir Fraser
- [Xen-devel] RE: TSC scaling and softtsc reprise, and PROPOSAL, Dan Magenheimer
- [Xen-devel] Re: TSC scaling and softtsc reprise, and PROPOSAL, Keir Fraser
- [Xen-devel] RE: TSC scaling and softtsc reprise, and PROPOSAL, Zhang, Xiantao
- [Xen-devel] RE: TSC scaling and softtsc reprise, and PROPOSAL, Dan Magenheimer
- [Xen-devel] Re: TSC scaling and softtsc reprise, and PROPOSAL, Keir Fraser
- [Xen-devel] RE: TSC scaling and softtsc reprise, and PROPOSAL, Dan Magenheimer
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