[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] Writing to a ramdisk in a PV domain is SLLLOOOWWW?!?
Has anyone tried using a ramdisk in a PV domain? I'm trying it in an experiment to compare swapping to a ramdisk against tmem (frontswap) performance (suggested as a performance test on lkml). Writing to the ramdisk appears to be VERY VERY slow, elapsed time in the guest is several times larger than user+sys, and xentop shows the guest consuming vcpu seconds at about the user+sys rate. Note that this is when tmem is turned off and there is no vhd swap disk configured. I'm suspecting that writing to ramdisk must be causing some interesting/expensive PV pagetable behavior? Or maybe somehow /dev/ram0 is getting routed through qemu? Or ?? Thanks, Dan P.S. Yes, I realize a ramdisk has no real value in a guest... this is just a performance experiment. _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
|
![]() |
Lists.xenproject.org is hosted with RackSpace, monitoring our |