On Tue, Jul 09, 2013 at 04:31:32PM +0200, Victor fernandez wrote: > 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). > Not all of them will be passed to a guest even with -cpu host, but instruction set related once like 3dnowext/3dnow you should be. What is qemu command line that you use? > 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. > > El 09/07/13 15:33, Gleb Natapov escribió: > >On Tue, Jul 09, 2013 at 02:20:43PM +0200, Victor fernandez wrote: > >>Hi EveryBody! > >> > >>recently, we have tested some specific High Energy Physics benchmarks that > >>was running over S.L.6 and we observed that the performance over AMD > >>machines was really bad, about 30-40% lost. We were investigating > >>and we conclude that the problem was with some cpu flags. These cpu > >>flags are important for running our application because it is optimazed > >>for running with them. So, we tuning our KVM with the name of flags > >>parameters and with "-cpu host" parameter too, but > >>we observed that the flags that we needed, they weren't included when > >>we started the S.L.6 instance. We try to solve it, but when we conclude > >>that the specific flags weren't included in the code of the last > >>versions of KVM > >>and LibVirt(capabilities). Do you know something about this problem or > >>you are aware of this? > >> > >What flags are missing? > > > >-- > > Gleb. > -- Gleb. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
