Video Memory

NoOp glgxg at
Mon Mar 2 19:10:32 UTC 2009

On 03/02/2009 03:38 AM, Ray Parrish wrote:

> So... I'm not too sure what this is saying, as I do not know what the 
> memory ranges are specifying for sure. The second memory range matches 
> the reported 256 MB's reported by most utilities in Ubuntu, and dividing 
> the last memory range by 1024 only once matches 128 MB's but that 
> decimal number before division is only 131070.999658496 so if it's in 
> bytes it doesn't make sense to only divide once.
> Anybody out there write device drivers for video cards?
> I guess I'll just have to continue to be mystified as to how much memory 
> my card is actually using.
> Later, Ray Parrish

My _guess_ would be that your card is using shared memory and with your
512MB of ram it's 'Total Effective Memory' is 256MB. See:


You might find these of interest:
[Memory management for graphics processors]

Also, to get an idea of what each of your processes are using in the way
of memory you can use pmap. You'll find this interesting:

$ pmap `pidof compiz.real`
$ pmap `pidof compiz.real` -d |more

and 'man pmap'

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