Fixed in version: kvm-83-183.el5
You have kvm-83-164.el5_5.15
On 09/08/10 15:34, Kirby Zhou wrote:
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
_______________________________________________
rhelv5-list mailing list
[email protected]
https://www.redhat.com/mailman/listinfo/rhelv5-list
