Hi Avi, I spoke to you a while ago on #kvm on freenode - I had a problem with ide ops on an amd svm host with kvm. The issues regarded the inability to access ida devices (hda/hdc) under qemu & kvm on my host - if this triggers your memory...
The last point I got to was that it was kvm and amd specific. Id est, the same image run under an intel vmx host with the *exact* same image, kvm version and command options (svn 'trunk' from the $date). The issue seemed to be AMD and kvm specific (running with '-no-kvm' made everything work ok, but slower, as you'd expect). I got word of a possible workaround, from one of your colleagues whilst you've been away, to use the boot options 'noapic nolapic' on the host o/s. Using these options solved my hd* op problems and I can boot ok now. It seems disabling the local apic was the fundamental part (iirc), as without host support the guest would always start the dummy apic; so running the guest with any 'special' options (ie. '-no-apic') should not be required. I'm think this problem is specific to my particular cpu/motherboard combination aswell. I also have box with a recent intel cpu (with the vmx extention) which doesn't display this behaviour; and from talking with you it's not purely amd specific (I believe your tests on amd cpu worked). Is it possible a slowdown in the interrupt controller between the guest and host is a contributing factor? Iirc, with a 'dummy' apic, I experience a ~5% slowdown on disk and network operations, which isn't so bad. I've yet to think about smp usage. Thought you might appreciate this info should you feel it deserve a wiki entry. Point me in the direction of the appropriate page should you feel I can put this info in myself. Best regards, Matt ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
