Hi there, I'm happy to see that TRANSPARENT_HUGEPAGES is included :)
As I promised I did some test. I installed a Natty guest onto the Natty host. The Natty guest was installed with the boot option to install a minimal virtual system, and in the tasksel session I chose Basic Ubunt server and OpenSSH server. Local file modifications in the guest means that I open and edit /etc/default/.* (ntpdate, rsyslog, ssh, etc.) Test cases without hugetlbfs: Test case 1.: Natty host + natty guest, 8192 MB RAM, without hugetlbfs, guest uses file backend, raw format, virtio disk and nic, KSM not running. Result: After the first 2-3 file copies the speed degraded to 40-50MB/sec, the load on the host is between 20-30 but the system is responsive, on the guest the load is between 2-3, opening and writing a file takes 6-14 seconds. After the 4-5th file copy the speed degraded to 14-15mb/s, the load on the host lowers to 5, in the guest 2, therefore modification of local files are speedy after the performance loss. Test case 2.: Natty host + natty guest, 8192 MB RAM, without hugetlbfs, guest uses file backend, raw format, virtio nic, IDE disk, KSM not running. Result: After the first 2-3 file copies the speed degraded to 30-40MB/sec, the load on the host is between 2-3 (that's ok), on the guest between 2-3, opening and writing a file takes 20-30 seconds. After the 4-5th file copy the speed degraded to 4-5mb/s, therefore modification of local files are speedy. Test case 3.: Natty host + natty guest, 8192 MB RAM, without hugetlbfs, guest uses file backend, raw format, virtio nic, IDE disk, KSM running. Result: After the first 3 file copies the speed degraded to 30-40MB/sec, the load on the host is between 2-3 (that's ok), on the guest between 2-3, opening and writing a file takes 10-20 seconds. After the 4-5th file copy the speed degraded to 4-5mb/s, therefore modification of local files are speedy. Test case 4.: Natty host + natty guest, 8192 MB RAM, without hugetlbfs, guest uses file backend, raw format, virtio disk and nic, KSM running. Result: Awfully slow. The first 1-2 file copies producing 40-60MB/sec, but the host load and guest load rising. Host load is about 10, guest load is about 2 but awfully slow. Local file modificiations in guest system takes at least 30 seconds (written to disk) and opening local files takes 30 seconds, as well. With hugetlbfs: Test case 5.: Natty host + natty guest, 8192 MB RAM, with hugetlbfs, guest uses file backend, raw format, virtio nic, IDE disk, KSM not running. Result: The host load stays under 1, the guest load goes up to 3, and stays contantly between 2 and 3. Copying the files stays at the same speed, between 55-70MB/sec but modification of local files take 15-30 seconds. Just opening them takes 5-8 seconds. Test case 6.: Natty host + natty guest, 8192 MB RAM, with hugetlbfs, guest uses file backend, raw format, virtio disk and nic, KSM not running. Result: Host system load goes up to 40-50 but hosts local disk I/O is fast. The disk I/O in guest slower. It takes 6-15 seconds to open a file and writing it out to the local filesystem of the guest takes 5-7 seconds to complete. Test case 7.: Natty host + natty guest, 8192 MB RAM, with hugetlbfs, guest uses file backend, raw format, virtio nic, IDE disk, KSM running. Result: The load on the hosts stays under 1 (0.8-0.9), so that's more than excellent, load inside the guest reaches between 1-2 but file modifications are somewhat slow. Sometimes it takes 10-15 seconds just to write a file ono the disk. Networking speed is always between 50-70MB/sec. 50-55MB/sec is the most usual (80%). Test case 8.: Natty host + natty guest, 8192 MB RAM, with hugetlbfs, guest uses file backend, raw format, virtio disk and nic, KSM running. Result: The load on the hosts stays under 1, so that's more than excellent, load inside the guest reaches 2-3 but file modifications are somewhat slow. Sometimes it takes 20-30 seconds just to write a file ono the disk. Networking speed is always between 50-70MB/sec. 50-55MB/sec is the most usual (90%). Tommorrow I will try to do the LVM partition test. Hope these tests are helpful. Cheers, Ago -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/769503 Title: KVM network I/O degraded using virtio and freezes guest sometimes -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
