On Thu, August 7, 2014 5:30 pm, Les Mikesell wrote: > On Thu, Aug 7, 2014 at 5:13 PM, Valeri Galtsev > <galtsev at kicp.uchicago.edu> wrote: >> >>>> >>>> ... And in addition to that, I need to have a 64-bit OS running on it, >>>> which I apparently don't. Just my luck. :-( >>>> >>> >>> Technically you don't need to have a 64-bit host OS to virtualize a >>> 64-bit guest but that may be the way kvm is built. I know I used to >>> run 64-bit linux versions under vmware player on a laptop running >>> 32-bit windows XP. Maybe virtualbox would work... >> >> To the best of my knowledge, vmware emulates generic CPU, therefore, >> guest >> can have different architecture from host. Emulates meaning, in >> particular, what is CPU register for guest is actually sitting in RAM. >> Therefore, regisetr-to-register operation for vmware guest ias asctually >> physical RAM to physical RAM operation which is a couple of orders on >> magnitude slower (well, was long ago, and I'm sure still is). > > I don't think that makes any sense in the context of CPU's with > hardware virtualization capability - which is necessary for 64-bit > guests anyway. And it doesn't match the speeds I've observed for > vmware vs kvm guests which seem about the same. It might be true when > running 32 bit guests on hosts where the CPU does not have hardware > virtualization support. Yes, I should have mentioned that. Vmware changed from emulating CPU to hardware virtualization some time ago. I was referring to older vmware virtualization for which it is possible to have different host and guest architecture. The last was mentioned in post I answered to... Sorry I introduced confusion. > > -- > Les Mikesell > lesmikesell at gmail.com > _______________________________________________ > CentOS mailing list > CentOS at centos.org > http://lists.centos.org/mailman/listinfo/centos > ++++++++++++++++++++++++++++++++++++++++ Valeri Galtsev Sr System Administrator Department of Astronomy and Astrophysics Kavli Institute for Cosmological Physics University of Chicago Phone: 773-702-4247 ++++++++++++++++++++++++++++++++++++++++