I think I have already applied this update: ]# rpm -q kvm kmod-kvm kvm-qemu-img kvm-tools kernel kvm-83-164.el5_5.15 kmod-kvm-83-164.el5_5.15 kvm-qemu-img-83-164.el5_5.15 kvm-tools-83-164.el5_5.15 kernel-2.6.18-194.8.1.el5
/dev/vgext/kvm-rhel5guest on host == /dev/vda on guest host]# ./randio /dev/vgext/kvm-rhel5guest 10 100000 -j crc32 -j md5 -t seq -Q -d total time=13.217346 io=100000 (7565.82/s) iosz=3200000k (242106.09k/s) rd=100000 (7565.82/s) rdsz=3200000k (242106.09k/s) wr=0 (0.00/s) wrsz=0k (0.00k/s) guest]# ./randio /dev/vda 10 100000 -j crc32 -j md5 -t seq -Q -d total time=23.319551 io=100000 (4288.25/s) iosz=3200000k (137223.91k/s) rd=100000 (4288.25/s) rdsz=3200000k (137223.91k/s) wr=0 (0.00/s) wrsz=0k (0.00k/s) Regards Kirby Zhou -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Alexander Dalloz Sent: Monday, August 09, 2010 8:45 PM To: 'Red Hat Enterprise Linux 5 discussion mailing-list' Subject: Re: [rhelv5-list] [rhelv6-beta-list] KVM performance is very poor? > KVM performance is very poor? > > I have tested a simple IO/CPU mixture testcase under both RHEL5/Xen and > RHEL6/KVM guest. > Under the naked machine, both RHEL5 and RHEL6 can get 250M/s, > XEN guest can get 240M/s > KVM guest can get only 120M/s > Regards > Kirby Zhou Do not know the KVM version you tested against. But on RHEL 5 there was a performance hitting bug https://rhn.redhat.com/errata/RHBA-2010-0536.html * the virtio-blk back end for qemu-kvm performed unnecessary zeroing of memory on every I/O request, which reduced virtual guest performance. With this update,t he virtio-blk back end avoids spurious zeroing of request structures on each I/O request, with the result that guest performance is increased. (BZ#604159) Alexander _______________________________________________ rhelv5-list mailing list [email protected] https://www.redhat.com/mailman/listinfo/rhelv5-list _______________________________________________ rhelv5-list mailing list [email protected] https://www.redhat.com/mailman/listinfo/rhelv5-list
