Am 08.11.2012 um 06:49 schrieb Dietmar Maurer <dietmar@xxxxxxxxxxx>: >>> I've noticed something really interesting. >>> >>> I get 5000 iops / VM for rand. 4k writes while assigning 4 cores on a >>> 2.5 Ghz Xeon. >>> >>> When i move this VM to another kvm host with 3.6Ghz i get 8000 iops >>> (still 8 >>> cores) when i then LOWER the assigned cores from 8 to 4 i get >>> 14.500 iops. If i assign only 2 cores i get 16.000 iops... >>> >>> Why does less kvm cores mean more speed? >> >> There is a serious bug in the kvm vhost code. Do you use virtio-net with >> vhost? >> >> see: http://lists.nongnu.org/archive/html/qemu-devel/2012- >> 11/msg00579.html >> >> Please test using the e1000 driver instead. > > Or update the guest kernel (what guest kernel do you use?). AFAIK 3.X kernels does not trigger the bug. Guest and Host habe 3.6.6 installed. > -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
