> -----Original Message----- > From: Kashyap Chamarthy [mailto:kashyap.cv@xxxxxxxxx] > Sent: Monday, May 13, 2013 3:07 PM > To: Ren, Yongjie > Cc: kvm@xxxxxxxxxxxxxxx > Subject: Re: [nVMX Test] Build kernel (defconfig) on L2, w/ VMCS > Shadowing enabled on L0 > > On Mon, May 13, 2013 at 11:51 AM, Kashyap Chamarthy > <kashyap.cv@xxxxxxxxx> wrote: > >> Thanks for the detailed configurations and steps about the nVMX test. > >> I have some suggestions if you want to test more: > >> 1. you can make L2 guest have 4vCPU and 4Mem > > > > Yeah, will try it. L0 has a max of 8G MEM. > > > >> 2. as L2 is SMP system, you can try 'time make -j 4' instead of 'time > make'. > > > > This is my next step :) . > > > >> 3. some performance comparison when enable/disable VMCS > shadowing > > > > Yes, as we speak, Kernel is building in L2 w/ VMCS Shadowing disabled > > on L0. I'll do two runs. > > Interesting: > > 1/ With VMCS Shadowing *disabled* : > > - On L0 (Side note: I did reboot the host, once I disabled shadow VMCS) > ==== > $ cat /sys/module/kvm_intel/parameters/enable_shadow_vmcs > N > ==== > > - Building Kernel on L2: > ==== > $ time make > ..... > real 36m33.361s > user 18m19.003s > sys 17m6.208s > ==== > > > 2/ With VMCS Shadowing *enabled* : > > - On L0 (Side note: I did reboot the host, once I enabled shadow VMCS) > ==== > $ cat /sys/module/kvm_intel/parameters/enable_shadow_vmcs > Y > ==== > > - Building Kernel on L2: > ==== > $ time make > ..... > real 62m53.853s > user 32m32.724s > sys 32m16.430s > ==== > > Comments ? > My test result is different from yours. In my test several days ago, when enabling shadow VMCS, I can get ~4% performance improvement in kernel build test in L2. Hardware is also a Haswell machine. shadow VMCS disabled, build time: 649 seconds shadow VMCS enabled, build time: 627 seconds. -- 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
