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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [Patch 2/4] Refining Xsave/Xrestore support
>>> On 28.10.10 at 09:52, Haitao Shan <maillists.shan@xxxxxxxxx> wrote: > Then I would prefer to write XCR0 unconditionally. Otherwise, I can > only refer to the approach for handling CR4 switches: reading CR4 > first and checking whether there is a need to write actually. > But I don't think <a read to XCR0 plus a data comparison> can save any > compared with one unconditional write to XCR0. > Are you OK with this? Depends on the performance expectations of xsetbv and xgetbv (and its comparison to moves from/to control registers). At least there's no word in the documentation that xsetbv would be serializing. I would hope Intel could at least provide approximate numbers... Jan _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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