[Fedora-xen] slow disk performance in Xen0 FC5

[Ashe Canvar]

Hi all,

My dom0 and domU machines are showing terrible disk performance degradation.

For instance my avg data read rate ( tested using hdparm -t /dev/hda)
is 55MB/s using the regular smp kernel but it falls to 2.6MB/s when I
boot into dom0. No other domains are runnign at this point. I have
looked for incrementing interrupts in ide0 , there are none. hdparm
shows that dma mode is enabled. dmesg shows that the same driver is
being used for both smp and dom0 cases ( Uniform Multi-Platform E-IDE
driver Revision: 7.00alpha2 ).

I have total of 2Gig RAM in the box and dom0 is restricted to 512M.

Any help appreciated !

Thanks,
-ashe

[root at medusa1 ~]# rpm -qa | grep -i xen
kernel-xenU-2.6.16-1.2080_FC5
kernel-xen0-2.6.16-1.2080_FC5
xen-3.0.1-4