Re: Possible regression: XEN 4.0.0 total_memory decrease

[Alex Williams <awilliams@iweb.com>]

Hello,

Both builds run a 64-bit Xen kernel and 64-bit Dom0 kernel.

(XEN)  Xen  kernel: 64-bit, lsb, compat32
(XEN)  Dom0 kernel: 64-bit, lsb, paddr 0xffffffff80200000 -> 
0xffffffff805d388c

As for the RAM:

Xen 3.4.2: (XEN) System RAM: 3946MB (4041012kB)
Xen 4.0.0: (XEN) System RAM: 4084MB (4182064kB)

I have also verified with only 2048MB installed in the system. Here are 
the results:

Xen 3.4.2: (XEN) System RAM: 2036MB (2084912kB)
Xen 4.0.0: (XEN) System RAM: 1898MB (1943860kB)

Still 150MB RAM missing... it appears this problem is static and 
independant of the amount of RAM installed in the system.

Regards,



Keir Fraser wrote:
> Are the hypervisor and dom0 kernel 64-bit or 32-bit? Xen prints a message
> "System RAM: xxx" early during boot. Do these differ significantly for you
> between 3.4.2 and 4.0.0?
> 
>  K.
> 
> On 15/04/2010 16:54, "Alex Williams" <awilliams@iweb.com> wrote:
> 
>> Hello,
>>
>> I noticed a significant *decrease* (150MB) in "total_memory" on a host
>> build using XEN 4.0.0 with kernel 2.6.18.
>>
>> Here are the details:
>>
>> Server = 4096MB RAM
>> XEN 3.4.2 + kernel 2.6.18: xm info | grep total_memory = 4084
>> XEN 4.0.0 + kernel 2.6.18: xm info | grep total_memory = 3946
>>
>> The exact same kernel config file was used for both builds. I also made
>> sure there is absolutely no difference on the hosts (while the builds
>> are created on a different machine).
>>
>> This seems like a regression, unless someone can provide suggestions on
>> how to correct this?
>>
>> Thanks.
>>
> 
> 
> 
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-- 
Alexander Williams
IT Architecture Specialist
Spécialiste de l'Architecture TI
http://www.iWeb.com/