On 2 Sep 2015, at 09:22, Pasi Kärkkäinen pasik@iki.fi wrote:
On Tue, Sep 01, 2015 at 06:47:18AM +0200, Christoph wrote:
Hi All
Hello,
it is possible to tune dom0/domU for better IO/network performance? Since I have changed to Cenots7 dom0, I have a really poor IO performance inside a PV VM.
I have already done what is described on http://wiki.xenproject.org/wiki/Tuning_Xen_for_Performance It is better now but still significantly worse than with centos6 dom0
my settings:
xen parameter: dom0_mem=1024M cpufreq=xen dom0_max_vcpus=2 dom0_vcpus_pin
xl sched-credit Cpupool Pool-0: tslice=30ms ratelimit=1000us Name ID Weight Cap Domain-0 0 1024 0 samael 1 256 0 satan 2 512 0 amon 3 256 0 leviathan 4 512 0
echo 1048576 > /proc/sys/net/ipv4/tcp_limit_output_bytes on dom0
the both domU's satan and leviathan are very IO performance oriented (NFS server and downloading vm)
Is there something more what I can do or try?
could it be a selinux issue? I have it in permissive mode there, not disabled. But permissive means only to collect the info not enforcing the rules...
(I use the xen45 pkgs)
You forgot to mention the most important thing.. what kind of performance numbers are you seeing? What are you expecting?
Thanks,
— Pasi
Here’s a useful disk i/o stress test program that I got good results with on openSUSE 13.1, by running it on several VM’s overnight:
Using Bonnie++ for filesystem performance benchmarking http://archive09.linux.com/feature/139742
HTH
Keith Roberts