Xen devel - Mar 2009 - 3D Mark differs a lot when testing on Native and xen machine

Hi,
         I confronted with an interesting problem. I have one machine with 2GB
RAM. I did the following experiments;
1)         When running vista based on xen such as domain vista, I assign it 1GB
memory and 1GB memory left for domain0; it can get a 3D Mark score: 269;
2)         After step 1, I plug 1GB memory and the physical memory of the
machine is changed to 1GB; in the native mode of vista, it gets a 3D Mark score:
200;
3)         After step 2, I changed my machine''s physical memory to 2GB,
run 3D Mark again, it gets a 3D Mark score: 271;

         Now I am confused about this problem: why native system with 1GB memory
gets a worse result comparing to virtual system with 1GB memory?
         Does the above domain vista use the memory of domain 0? Or it
won''t get nearly the same result as native system with 2GB physical
memory.

Thanks


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>          I confronted with an interesting problem. I have one machine
> with 2GB RAM. I did the following experiments;
> 
> 1)         When running vista based on xen such as domain vista, I
> assign it 1GB memory and 1GB memory left for domain0; it can get a 3D
> Mark score: 269;
> 
> 2)         After step 1, I plug 1GB memory and the physical memory of
> the machine is changed to 1GB; in the native mode of vista, it gets a
> 3D Mark score: 200;
Does your chipset support dual memory channels? If so, removing the DIMM may
have halved your memory bandwidth.

Ian

 
> 3)         After step 2, I changed my machine''s physical memory to
2GB,
> run 3D Mark again, it gets a 3D Mark score: 271;
> 
> 
> 
>          Now I am confused about this problem: why native system with
> 1GB memory gets a worse result comparing to virtual system with 1GB
> memory?
> 
>          Does the above domain vista use the memory of domain 0? Or it
> won''t get nearly the same result as native system with 2GB
physical
> memory.
> 
> 
> 
> Thanks

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Xen-devel@lists.xensource.com
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Thanks.
It seems to be the true root


Thanks
-----Original Message-----
From: Ian Pratt [mailto:Ian.Pratt@eu.citrix.com] 
Sent: 2009年3月11日 19:37
To: Xia, Liangfu; xen-devel@lists.xensource.com
Cc: Ian Pratt
Subject: RE: [Xen-devel] 3D Mark differs a lot when testing on Native and xen
machine
>          I confronted with an interesting problem. I have one machine
> with 2GB RAM. I did the following experiments;
> 
> 1)         When running vista based on xen such as domain vista, I
> assign it 1GB memory and 1GB memory left for domain0; it can get a 3D
> Mark score: 269;
> 
> 2)         After step 1, I plug 1GB memory and the physical memory of
> the machine is changed to 1GB; in the native mode of vista, it gets a
> 3D Mark score: 200;
Does your chipset support dual memory channels? If so, removing the DIMM may
have halved your memory bandwidth.

Ian

 
> 3)         After step 2, I changed my machine's physical memory to 2GB,
> run 3D Mark again, it gets a 3D Mark score: 271;
> 
> 
> 
>          Now I am confused about this problem: why native system with
> 1GB memory gets a worse result comparing to virtual system with 1GB
> memory?
> 
>          Does the above domain vista use the memory of domain 0? Or it
> won't get nearly the same result as native system with 2GB physical
> memory.
> 
> 
> 
> Thanks

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Xen-devel@lists.xensource.com
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