[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] Re: Poor performance on HVM (kernbench)
another number Xen 3.2.1 HVM guest, much faster than on 3.3/unstable Elapsed Time 834.082 (3.25046) User Time 492.68 (1.61651) System Time 328.778 (1.78148) Percent CPU 98 (0) Context Switches 146272 (437.262) Sleeps 36858 (127.805) On Wed, Sep 10, 2008 at 2:23 PM, Todd Deshane <deshantm@xxxxxxxxx> wrote: > Hi All, > > We are continuing our Xen vs. KVM benchmarking that I presented at Xen summit. > > This time, we are focusing on newer versions and also planning to > include Xen HVM > and KVM with PV drivers results. As well as adding some more tests. > > I have setup Xen 3.3 from source, and am using Linux 2.6.27-rc4 for > all the guests. > > Below are some raw kernbench results, which clearly show that I have a problem > with Xen HVM. It may just be a configuration issue, but we have tried > all that we > could think of so far (i.e file:, instead of tap:aio). I have also > tried xen-unstable and > it doesn't seem to produce any better results. I am also in the > process of trying > kernbench on older versions of Xen HVM. > > here is the xm command line > xm create /dev/null name=benchvm0 memory=2048 > kernel="/usr/lib/xen/boot/hvmloader" builder="hvm" > device_model=/usr/lib64/xen/bin/qemu-dm > disk=file:/root/benchvm/bin/img-perf_xen_hvm_test1/image-0.img,hda,w > vnc=1 vncdisplay=0 vif=mac=AA:BB:CC:DD:EE:00,bridge=br0 > vif=mac=AA:BB:CC:DD:EE:7b,bridge=br1 vncviewer="yes" > on_poweroff=destroy on_reboot=restart on_crash=preserve > > I will also consider an IO test, such as iozone to see if > the disk IO problems are a cause. The dom0 cpu > doesn't seem to be under much load at all during the > kernbench run. > > System time on the kernbench run is 1/2 of the time, so does > that suggest either disk IO or guest scheduling problem? > > System time on the other cases is 1/4 or less on the other > cases. > > If anybody has any ideas, suggestions, or can even run Xen HVM kernbench > vs. native on their setup to compare against that would be very helpful. > > The system setup is a Intel core2 dual 4 GB of ram. > The HVM guest does run the libata driver similar to KVM with emulated drivers. > > Thanks, > Todd > > KVM PV drivers > > Average Optimal load -j 4 Run (std deviation): > Elapsed Time 527.572 (0.681337) > User Time 404.3 (0.982141) > System Time 122.552 (0.468636) > Percent CPU 99 (0) > Context Switches 116020 (180.82) > Sleeps 31307 (94.2072) > > > KVM Emulated drivers > > Average Optimal load -j 4 Run (std deviation): > Elapsed Time 527.968 (0.450744) > User Time 403.95 (0.342929) > System Time 122.134 (0.550709) > Percent CPU 99 (0) > Context Switches 115907 (214.3) > Sleeps 31302.4 (88.7175) > > Xen PV > > Average Optimal load -j 4 Run (std deviation): > Elapsed Time 446.876 (0.130115) > User Time 392.088 (0.339367) > System Time 54.76 (0.391088) > Percent CPU 99 (0) > Context Switches 64601.4 (163.314) > Sleeps 31214.8 (183.53) > > > > Xen HVM > > Average Optimal load -j 4 Run (std deviation): > Elapsed Time 2081.71 (34.0459) > User Time 617.36 (3.61771) > System Time 1430.36 (28.3309) > Percent CPU 98 (0) > Context Switches 331843 (5283.28) > Sleeps 37329.8 (91.538) > > > KVM Native (Linux) > > Average Optimal load -j 8 Run (std deviation): > Elapsed Time 216.076 (0.121778) > User Time 381.122 (0.259557) > System Time 43.242 (0.278783) > Percent CPU 196 (0) > Context Switches 75483.2 (389.988) > Sleeps 38078.8 (354.267) > > > Xen native 2.6.18.8 dom0 kernel > > Average Optimal load -j 8 Run (std deviation): > Elapsed Time 228.504 (0.0808084) > User Time 384.014 (0.657632) > System Time 64.028 (0.733669) > Percent CPU 195.8 (0.447214) > Context Switches 35270.4 (264.36) > Sleeps 39493.4 (266.222) > -- Todd Deshane http://todddeshane.net check out our book: http://runningxen.com _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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