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John O'Donnell | 11 Dec 2011 10:30
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qemu memory limitation

Stuart,
I notice that the 256M memory limitation still exists in the qemu 1.0 latest 
release yet google's android qemu variant can go well above.  If I have 8gigs of 
RAM, why cant I just create a X gig amount of ram disk and make that swap space 
(virtual RAM) within the qemu virtual machine... Wouldnt that still be faster? 
I havent tried this yet.  I was wondering if you had.
THanks
John

--

-- 
=== Never ask a geek why, just nod your head and slowly back away.===
+================================+==================================+
|  John O'Donnell                |                                  |
|  (Sr. Systems Engineer,        |    http://juanisan.homeip.net    |
|  Net Admin, Programmer, etc.)  |  E-Mail: unixjohn1969 <at> gmail.com  |
+================================+==================================+
No man is useless who has a friend, and if we are loved we are
indispensable.  -- Robert Louis Stevenson
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Stuart Winter | 12 Dec 2011 23:48
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Re: qemu memory limitation


> I notice that the 256M memory limitation still exists in the qemu 1.0 latest
> release yet google's android qemu variant can go well above.  If I have 8gigs
> of RAM, why cant I just create a X gig amount of ram disk and make that swap
> space (virtual RAM) within the qemu virtual machine... Wouldnt that still be
> faster? I havent tried this yet.  I was wondering if you had.

Nope. I use real machines -- give it a go though! It makes sense to me..

--

-- 
Stuart Winter
Slackware ARM: www.armedslack.org
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Ottavio | 13 Dec 2011 01:11
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Re: qemu memory limitation

On 11 December 2011 09:30, John O'Donnell <unixjohn1969 <at> gmail.com> wrote:
>  If I have 8gigs of RAM, why cant I just create a X gig amount of ram disk
> and make that swap space (virtual RAM) within the qemu virtual machine...

Is there any real life ARM device that supports 8G RAM?

--

-- 
Ottavio

qemu-users: http://groups.yahoo.com/group/qemu-users/
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Davide | 13 Dec 2011 09:06
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Re: qemu memory limitation

ARMv8 is supposed to support 64 bit addressing otherwise as far as I know all current ARM devices have sub 32 bit address space.

Ciao for now
David
Da: Ottavio <pr0f3ss0r1492 <at> yahoo.com>
A: Slackware ARM port <armedslack <at> lists.armedslack.org>
Inviato: Martedì 13 Dicembre 2011 1:11
Oggetto: Re: [ARMedslack] qemu memory limitation

On 11 December 2011 09:30, John O'Donnell <unixjohn1969 <at> gmail.com> wrote:
>  If I have 8gigs of RAM, why cant I just create a X gig amount of ram disk
> and make that swap space (virtual RAM) within the qemu virtual machine...

Is there any real life ARM device that supports 8G RAM?



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Ottavio

qemu-users: http://groups.yahoo.com/group/qemu-users/
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John O'Donnell | 13 Dec 2011 09:14
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Re: qemu memory limitation

On 12/12/2011 07:11 PM, Ottavio wrote:
> On 11 December 2011 09:30, John O'Donnell<unixjohn1969 <at> gmail.com>  wrote:
>>   If I have 8gigs of RAM, why cant I just create a X gig amount of ram disk
>> and make that swap space (virtual RAM) within the qemu virtual machine...
>
> Is there any real life ARM device that supports 8G RAM?

I dont know.  All I know is I need more than 512M.  I am experimenting with QT. 
Compiling it on a current Sheeva/Guru plug takes 3 days with about 2gb of swap. 
  If I can get more memory to toy with then it will make life so much easier. 
After I get my results, I will spend the 3 days to get a compile on hardware.

John

--

-- 
=== Never ask a geek why, just nod your head and slowly back away.===
+================================+==================================+
|  John O'Donnell                |                                  |
|  (Sr. Systems Engineer,        |    http://juanisan.homeip.net    |
|  Net Admin, Programmer, etc.)  |  E-Mail: unixjohn1969 <at> gmail.com  |
+================================+==================================+
No man is useless who has a friend, and if we are loved we are
indispensable.  -- Robert Louis Stevenson
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Ottavio | 13 Dec 2011 10:56
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Re: qemu memory limitation

On 13 December 2011 08:14, John O'Donnell <unixjohn1969 <at> gmail.com> wrote:
> On 12/12/2011 07:11 PM, Ottavio wrote:
>>
>> On 11 December 2011 09:30, John O'Donnell<unixjohn1969 <at> gmail.com>  wrote:
>>>
>>>  If I have 8gigs of RAM, why cant I just create a X gig amount of ram
>>> disk
>>> and make that swap space (virtual RAM) within the qemu virtual machine...
>>
>>
>> Is there any real life ARM device that supports 8G RAM?
>
>
> I dont know.  All I know is I need more than 512M.  I am experimenting with
> QT. Compiling it on a current Sheeva/Guru plug takes 3 days with about 2gb
> of swap.  If I can get more memory to toy with then it will make life so
> much easier. After I get my results, I will spend the 3 days to get a
> compile on hardware.

I see these two options in the qemu manual:

-mem-path path
    Allocate guest RAM from a temporarily created file in path.
-mem-prealloc
    Preallocate memory when using -mem-path.

I have never tried.

--

-- 
Ottavio

qemu-users: http://groups.yahoo.com/group/qemu-users/
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John O'Donnell | 13 Dec 2011 11:37
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Re: qemu memory limitation

On 12/13/2011 04:56 AM, Ottavio wrote:
>>>>   If I have 8gigs of RAM, why cant I just create a X gig amount of ram
>>>> disk
>>>> and make that swap space (virtual RAM) within the qemu virtual machine...
>>>
>>> Is there any real life ARM device that supports 8G RAM?
>>
>> I dont know.  All I know is I need more than 512M.  I am experimenting with
>> QT. Compiling it on a current Sheeva/Guru plug takes 3 days with about 2gb
>> of swap.  If I can get more memory to toy with then it will make life so
>> much easier. After I get my results, I will spend the 3 days to get a
>> compile on hardware.
>
> I see these two options in the qemu manual:
>
> -mem-path path
>      Allocate guest RAM from a temporarily created file in path.
> -mem-prealloc
>      Preallocate memory when using -mem-path.
>
> I have never tried.

hmmm nice find!  I suspect these only affect main ram usage within the guest as 
such the 256M qemu limitation would still apply, but I'll give it a try!

Thanks again!
John

--

-- 
=== Never ask a geek why, just nod your head and slowly back away.===
+================================+==================================+
|  John O'Donnell                |                                  |
|  (Sr. Systems Engineer,        |    http://juanisan.homeip.net    |
|  Net Admin, Programmer, etc.)  |  E-Mail: unixjohn1969 <at> gmail.com  |
+================================+==================================+
No man is useless who has a friend, and if we are loved we are
indispensable.  -- Robert Louis Stevenson
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Jim Hawkins | 13 Dec 2011 12:52
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Re: qemu memory limitation

On Tue, 13 Dec 2011, John O'Donnell wrote:

> On 12/13/2011 04:56 AM, Ottavio wrote:
> > I see these two options in the qemu manual:
> > 
> > -mem-path path
> >      Allocate guest RAM from a temporarily created file in path.
> > -mem-prealloc
> >      Preallocate memory when using -mem-path.
> > 
> > I have never tried.
> 
> hmmm nice find!  I suspect these only affect main ram usage within the guest
> as such the 256M qemu limitation would still apply, but I'll give it a try!

AIUI, the RAM limit in qemu is platform dependant. The versatilepb 
platform is limited to 256MB, but according to the following 
page, the vexpress-a9 platform supports up to 1GB RAM:

https://wiki.linaro.org/PeterMaydell/QemuVersatileExpress

Although it will probably will take a bit more effort to get working than 
just changing the machine type on the qemu command line.

Cheers,

Jim
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Stuart Winter | 13 Dec 2011 13:48
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Re: qemu memory limitation


> AIUI, the RAM limit in qemu is platform dependant. The versatilepb
> platform is limited to 256MB, but according to the following
> page, the vexpress-a9 platform supports up to 1GB RAM:
>
> https://wiki.linaro.org/PeterMaydell/QemuVersatileExpress
>
> Although it will probably will take a bit more effort to get working than
> just changing the machine type on the qemu command line.

I might look at this later and replace the Versatile support with the
Versatile Express.  After all, the only aim is to 'showcase' Slackware ARM
without having any real ARM hardware (although the original reason was
because my RiscPC broke down and I had no substitute).
Perhaps when I've finished adding support for the Trimslice, I'll look at
this.
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Stuart Winter | 14 Dec 2011 23:08
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Re: qemu memory limitation

> AIUI, the RAM limit in qemu is platform dependant. The versatilepb
> platform is limited to 256MB, but according to the following
> page, the vexpress-a9 platform supports up to 1GB RAM:
>
> https://wiki.linaro.org/PeterMaydell/QemuVersatileExpress
>
> Although it will probably will take a bit more effort to get working than
> just changing the machine type on the qemu command line.

So this one has no SCSI or IDE bus - just SD card.  That limits it as far
as Slackware is concerned :-(
I don't want to trade RAM for a lack of addressable standard storage.

--

-- 
Stuart Winter
Slackware ARM: www.armedslack.org
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Greg Lim | 13 Dec 2011 19:01
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Re: qemu memory limitation


On Dec 13, 2011, at 3:14 AM, John O'Donnell <unixjohn1969 <at> gmail.com> wrote:

> On 12/12/2011 07:11 PM, Ottavio wrote:
>> On 11 December 2011 09:30, John O'Donnell<unixjohn1969 <at> gmail.com>  wrote:
>>>  If I have 8gigs of RAM, why cant I just create a X gig amount of ram disk
>>> and make that swap space (virtual RAM) within the qemu virtual machine...
>> 
>> Is there any real life ARM device that supports 8G RAM?
> 
> I dont know.  All I know is I need more than 512M.  I am experimenting with QT. Compiling it on a current
Sheeva/Guru plug takes 3 days with about 2gb of swap.  If I can get more memory to toy with then it will make
life so much easier. After I get my results, I will spend the 3 days to get a compile on hardware.
> 
> John
> 
> -- 
> === Never ask a geek why, just nod your head and slowly back away.===
> +================================+==================================+
> |  John O'Donnell                |                                  |
> |  (Sr. Systems Engineer,        |    http://juanisan.homeip.net    |
> |  Net Admin, Programmer, etc.)  |  E-Mail: unixjohn1969 <at> gmail.com  |
> +================================+==================================+
> No man is useless who has a friend, and if we are loved we are
> indispensable.  -- Robert Louis Stevenson
> _______________________________________________
> ARMedslack mailing list
> ARMedslack <at> lists.armedslack.org
> http://lists.armedslack.org/mailman/listinfo/armedslack

If you really need to speed up builds and you have a spare SATA port or 2, you could use one of these:
http://www.acard.com.tw/english/fb01-product.jsp?idno_no=270&prod_no=ANS-9010&type1_title=%20Solid%20State%20Drive&type1_idno=13

I used one for a bit as swap/tmp/build space and it helped.

-Greg Lim
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