[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] RE: [Xen-users] XP HVM performance
> > I recently reinstalled an XP over my xen 3.2.1 (my conf is at the end of > the mail). > > And it's working but I find it a bit (well a big bit ...) too slow and > use a lot of CPU. > > For instance just having a taskmanager running use between 10/15% of CPU > as reported by taskmanager and xm top. > > When I run iozone the CPU usage is almost 95% whereas on a real XP > workstation it's only a few percents. > > The server hosting this XP is a 4 core Xeon E5320 @ 1.86GHz and I have > only dom0 with 2 VCPU and 1 VCPU in XP. > > I know that running XP in XEN will bring a penalty but I wasn't > expecting such penalty. > > Do I miss something ? > > I also use the latest GPL PV drivers and found with iozone that the > throughput is 1/3 of the raw capacity of the disk (as measured in dom0). > Does this number seems normal to you or once more am I missing something ? > > Finally I also did some tests with more than one VCPU but if the whole > system load reduced somehow (which is logical) the IO perf where even > worse. Is it a good idea to use more than one VCPU in HVM ? > Please try putting /PATCHTPR in your boot.ini (make a copy of the existing line in case it causes a problem). That will get GPLPV to patch the windows kernel to stop using one of the hardware APIC registers so often (intel) or at all (amd). Let me know if that affects the speed in any way. On an Intel processor you will get about 50% of the performance improvement that you would with an AMD processor, but it still makes a big difference. I'm not sure but I think that later versions of Xen include a hypervisor-side speedup for Intel which would make /PATCHTPR unnecessary. Anyway, please try it and let me know. James _______________________________________________ Xen-users mailing list Xen-users@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-users
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