Re: AW: AW: AW: AW: AW: KVM performance
BRAUN, Stefanie wrote: Hello, I've compiled a new kernel v2.6.27-rc5 with the modified svm.c. But the behaviour of the vlc process in the guest is still the same. I've exported additional cpu features to the guest, e.g. mmxext with kvm-84. But no performance changes. I was not able to export the cpu flags 3dnow and 3dnowext to the guest, no error but they are not visible in /proc/cpuinfo. Not sure why. Can you test on an intel host (relative performance host vs guest)? -- Do not meddle in the internals of kernels, for they are subtle and quick to panic. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
AW: AW: AW: AW: AW: KVM performance
Hello, I've compiled a new kernel v2.6.27-rc5 with the modified svm.c. But the behaviour of the vlc process in the guest is still the same. I've exported additional cpu features to the guest, e.g. mmxext with kvm-84. But no performance changes. I was not able to export the cpu flags 3dnow and 3dnowext to the guest, no error but they are not visible in /proc/cpuinfo. Not sure why. Regards Stefanie BRAUN, Stefanie wrote: > qemu-kvm -cpu ? only shows > qemu64, qemu32, 486, pentium, pentium2, pentium3, athlon > It can also take additional +feature or -feature parameters. Oh, maybe kvm-84 doesn't have this support? try http://userweb.kernel.org/~avi/kvm-85rc6/. -Ursprüngliche Nachricht- Von: Avi Kivity [mailto:a...@redhat.com] Gesendet: Dienstag, 14. April 2009 10:48 An: BRAUN, Stefanie Cc: kvm@vger.kernel.org Betreff: Re: AW: AW: AW: AW: KVM performance BRAUN, Stefanie wrote: > Hello, > the host runs on a Dual-Core AMD Opteron Processor. > Does there exist a similar AMD parameter? > You can add individual host cpu features by using '-cpu qemu64,+feature', where feature is taken from the host /proc/cpuinfo. Do you know which cpu features the program can take advantage of? Also please try replacing the constant 0x0007040600070406ULL in kernel/x86/svm.c with 0x0606060606060606ULL and see what happens (don't forget to reload the modules). -- I have a truly marvellous patch that fixes the bug which this signature is too narrow to contain. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: AW: AW: AW: AW: KVM performance
BRAUN, Stefanie wrote: Hello, the host runs on a Dual-Core AMD Opteron Processor. Does there exist a similar AMD parameter? You can add individual host cpu features by using '-cpu qemu64,+feature', where feature is taken from the host /proc/cpuinfo. Do you know which cpu features the program can take advantage of? Also please try replacing the constant 0x0007040600070406ULL in kernel/x86/svm.c with 0x0606060606060606ULL and see what happens (don't forget to reload the modules). -- I have a truly marvellous patch that fixes the bug which this signature is too narrow to contain. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
AW: AW: AW: AW: KVM performance
Hello, the host runs on a Dual-Core AMD Opteron Processor. Does there exist a similar AMD parameter? Regard Stefanie -Ursprüngliche Nachricht- Von: Avi Kivity [mailto:a...@redhat.com] Gesendet: Samstag, 11. April 2009 18:19 An: BRAUN, Stefanie Cc: kvm@vger.kernel.org Betreff: Re: AW: AW: AW: KVM performance BRAUN, Stefanie wrote: > Hello, > > now I was able to start the guest vmu with disk virtio, and some of > the tests with disk involvement even improved a bit. > But the test in which a logo is added to the video stream does not > improve. I don't know why the performance is so bad? > > Subtest: Reading video locally, adding a logo to the video stream and > then saving the video locally > Host performance: 50% > kvm process in host (top) : 99% > vlc process in vmu (top) : 99% > > > The output of kvm_stat -1 during the subtest is the following: > > efer_reload0 0 > exits9913473 3994 > This indicates that kvm is running in guest mode all of the time and is therefore quite efficient. Perhaps the test uses sse instructions which kvm doesn't expose? Try adding -cpu core2duo to the command line. -- Do not meddle in the internals of kernels, for they are subtle and quick to panic. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
