Shouta, Can it be reproduced if thp/hugetlbfs is disabled on both source and destination? On 11/01/2012 08:12 AM, Shouta.Uehara@xxxxxxxxxxxxxxx wrote: > Hello. > > I have a problem with the performance of the guest Linux after live migration. > When I analyze the file I/O latency of the guest using LMbench3, the latency of > the guest on the destination host is about 2 times bigger than the guest on the > source host. As a result that I investigated it, this problem occurs if three > following conditions are right. > > 1. Use the kernel version 2.6.38.6-26.fc15.x86_64 or later. > 2. Execute system calls for low level file I/O (read, write, open etc.) on the > guest. > 3. Enable EPT. > > Performance cannot decrease on other tests of LMbench3; numerical operation, > context switching, memory latencies etc. > > Is this an existing problem ? What should I do to resolve it ? > > --- > The situation the problem occurs > > CPU models : Intel Xeon E3-1245 (Both hosts have same cpu.) > Host kernel : 3.6.4 > Host OS : Fedora 16 64bit ver. (Both hosts have same OS.) > Guest OS : Fedora 16 64bit ver., kernel 3.1.0-7.fc16.x86_64 > QEMU version : qemu-kvm 1.2.0 > QEMU parameter : qemu-kvm -m 1024 -drive file=guest.qcow2,if=virtio \ > -boot order=c,menu=on -k ja > (-incoming tcp:192.168.0.51:4444 set only destination) > QEMU command : migrate -d tcp:192.168.0.51:4444 > Analyses : LMbench version 3 > > [Guest on the source host] > $ ./lat_syscall open > Simple open/close: 1.4281 microseconds > $ ./lat_syscall read > Simple read: 0.1416 microseconds > $ ./lat_syscall write > Simple write: 0.1194 microseconds > $ ./lat_fs -s 0 > 0k 550 98726 247712 > 1k 383 69751 193985 > 4k 381 69348 193383 > 10k 313 54369 155697 > > [Guest on the source host] > $ ./lat_syscall open > Simple open/close: 1.6126 microseconds > $ ./lat_syscall read > Simple read: 0.2206 microseconds > $ ./lat_syscall write > Simple write: 0.1980 microseconds > $ ./lat_fs -s 0 > 0k 427 83252 243222 > 1k 315 60530 191650 > 4k 184 34535 190947 > 10k 65 11922 152608 > --- > > Thanks. > > Shota Uehara <Shouta.Uehara()jp.yokogawa.com> > > > ----- > CONFIDENTIAL: This e-mail may contain information that is confidential or otherwise protected from disclosure and intended only for the party to whom it is addressed. If you are not the intended recipient, please notify the sender by return and delete this e-mail. You are hereby formally advised that any unauthorized use, disclosure or copying of this email is strictly prohibited and may be unlawful. > -- > 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 > > -- 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
