[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] RE: [Xen-ia64-devel] One unstablity in fast syscall path
> > > On this point VTi may have a real advantage over > paravirtualization. > > > > Could you explain further? > Yes. > The virtualization handler has the opcode in GR25. > I don't know the amount of PAL code involved, but the > hardware might provides > the opcode directly from the pipeline. The VM doesn't have > to do the fecth, > which is time and cache consuming. No the hardware does not provide the opcode directly, though perhaps it will in future (post-Montecito) implementations. I believe that PAL is doing the same thing that Xen is doing to fetch the opcode, except since it is doing it sooner, there is a higher probability that it will be successful. And I suspect that it may be doing the "slow path" every time as it is probably not capable of handling (and recovering from) TLB misses. I'm not sure I would call this an advantage. Perhaps Intel can comment more here... I'm not sure what info is public. Dan _______________________________________________ Xen-ia64-devel mailing list Xen-ia64-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-ia64-devel
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