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[Xen-devel] Re: [Xen-users] how to disable batching of page table entrie

To: Qiang Zeng <zengqiang.buaa@xxxxxxxxx>
Subject: [Xen-devel] Re: [Xen-users] how to disable batching of page table entries updates for guest OS
From: Joseph Glanville <joseph.glanville@xxxxxxxxxxxxxx>
Date: Tue, 10 May 2011 12:27:06 +1000
Cc: xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>
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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.


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,
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