Re: Lost of performance over AMD-V with KVM?

[Victor fernandez <Victormanuel.fernandez@usc.es>]

Hi Gleb,

     there are flags that with the tuning of KVM (-cpu host) we get that 
some of
     important cpu flags are not included in SL6 ( Ht, rdtscp, 3dnowext, 
3dnow,
constant_tsc,nonstop_tsc,amd_dcm,monitor,svm,extapic,osvw,ibs,skinit,wdt,nodeid_msr).

     And the machines used for testing were 2 nodes AMD 6128 - 2Ghz - 2 
CPUs
     (8 Cores/CPU Core - 1GB) 16 Cores Total - 16 GB RAM for AMD-V 
virtualization,
     and we did the same tests with the same software versions with 2 
nodes of DELL
     PowerEdge SC1950, biprocessors dual core, 2 Xeon(R) CPU 5160 @ 
3.00GHz,
     16GB RAM. for Intel VT virtualization. And with Intel technology we 
get the
     typical virtualization performance, around 2-5% of lost.

      Thanks in advance,
         Víctor Fdez.