[Xen-devel] Re: [Xen-users] how to disable batching of page table entries updates for guest OS

[Joseph Glanville <joseph.glanville@xxxxxxxxxxxxxx>]

Hi,

This is a much better question for the xen-devel list.
I am cc'ing the list in.

Sounds like an intersting experiment however, goodluck.

Joseph.

On 9 May 2011 12:27, Qiang Zeng <zengqiang.buaa@xxxxxxxxx> wrote:
> Xen has a perf. enhancement by batching page table updates for the guest OS.
> I'm trying to measure the impact on the guest OS's performance, when this
> enhancement is disabled.
>
> But I don't know how to disable it. I tried modifying do_mmu_update in
> xen/arch/x86/mm.c, which is to process the batch of page table updates
> requested by the guest OS. I simply limit it to only process one update:
>
> << for ( i = 0; i < count; i++ )
>
>>> for ( i= 0; i < 1; i++)
>
> However, after I install this version, there is a kernel panic.
>
> An alternative may be to modify the code in the paravirtualized guest OS
> code, but I prefer to change xen code. Or do I HAVE to change the OS code
> rather than xen?
>
> Could somebody provide some hints? Thanks!
>
> Qiang.
>
> _______________________________________________
> Xen-users mailing list
> Xen-users@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-users
>



-- 
Kind regards,
Joseph.
Founder | Director
Orion Virtualisation Solutions | www.orionvm.com.au | Phone: 1300 56
99 52 | Mobile: 0428 754 846

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