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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH] TSC scaling for live migration between platforms with different TSC frequecies
Stuffing the guest freq in a save-image pad field is not backward compatible. Old images will not have that field filled in and you'll probably end up doing something stupid like give them a zero-hertz TSC. Please think about backward compatibility and use a separate save record. Like Tim asked you to do already. -- Keir On 22/06/2009 06:14, "Zhang, Xiantao" <xiantao.zhang@xxxxxxxxx> wrote: > Hi, Keir > This is the new version which has addressed the comments from the mailing > list. Please review it again. Thanks! > Xiantao > > Zhang, Xiantao wrote: >> Hi, Keir >> >> This patchset targets for enabling TSC scaling in software for >> live migration between platforms with different TSC frequecies. >> Once found the target host's frequency is different with source >> host's, hypervisor will trap and emulate guest's all rdtsc >> instructions with its expected frequency. If hardware's TSC frequency >> is difffernt with guest's exepcted freq, guest may behave abnormally, >> eg. incorrect wallclock, soft lockup, even hang in some cases. >> Therefore, this patchset is necessary to avoid such issues. >> >> PATCH 0001-- Save guest's preferred TSC in image for save/restore and >> migration >> PATCH 0002-- Move multidiv64 as a library function. >> PATCH 0003-- Scaling host TSC freqeuncy patch. >> >> Signed-off-by Xiantao Zhang <xiantao.zhang@xxxxxxxxx> >> Xiantao > _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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