Messages in this thread | | | Date | Thu, 13 Nov 2014 10:21:01 +0100 | From | Juergen Gross <> | Subject | Re: [Xen-devel] [PATCH V3 7/8] xen: switch to linear virtual mapped sparse p2m list |
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On 11/11/2014 06:47 PM, David Vrabel wrote: > On 11/11/14 05:43, Juergen Gross wrote: >> At start of the day the Xen hypervisor presents a contiguous mfn list >> to a pv-domain. In order to support sparse memory this mfn list is >> accessed via a three level p2m tree built early in the boot process. >> Whenever the system needs the mfn associated with a pfn this tree is >> used to find the mfn. >> >> Instead of using a software walked tree for accessing a specific mfn >> list entry this patch is creating a virtual address area for the >> entire possible mfn list including memory holes. The holes are >> covered by mapping a pre-defined page consisting only of "invalid >> mfn" entries. Access to a mfn entry is possible by just using the >> virtual base address of the mfn list and the pfn as index into that >> list. This speeds up the (hot) path of determining the mfn of a >> pfn. >> >> Kernel build on a Dell Latitude E6440 (2 cores, HT) in 64 bit Dom0 >> showed following improvements: >> >> Elapsed time: 32:50 -> 32:35 >> System: 18:07 -> 17:47 >> User: 104:00 -> 103:30 >> >> Tested on 64 bit dom0 and 32 bit domU. > > Reviewed-by: David Vrabel <david.vrabel@citrix.com> > > Can you please test this with the following guests/scenarios. > > * 64 bit dom0 with PCI devices with high MMIO BARs.
I'm not sure I have a machine available with this configuration.
> * 32 bit domU with PCI devices assigned. > * 32 bit domU with 64 GiB of memory. > * domU that starts pre-ballooned and is subsequently ballooned up. > * 64 bit domU that is saved and restored (or local host migration) > * 32 bit domU that is saved and restored (or local host migration)
I'll try.
Juergen
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