[GRASS-user] Re: [GRASS-windows] Virtual memory available to cygwin GRASS

[Luigi Ponti]

Hamish wrote:
> Luigi Ponti wrote:
>   
>> As a less-than-two-year old cygwin/GRASS user, I have never seen
>> virtual memory going over 1 GB while doing intensive computations
>> with GRASS (e.g., v.surf.idw interpolation).
>>     
>
> Have you been getting out-of-memory errors or are you concerned that
> you are not making best use of all available resouces? 
Yes: the latter.
> If the latter,
> you don't see grass using much memory because it is fairly efficent
> most of the time and doesn't need to- especially the core GIS and
> raster parts of it. When you consider the amount of RAM+CPU power
> typically available back when that code was written, it isn't
> surprising that it was done in such a way.
>   
Thanks Hamish, I see your point. What I don't quite understand is why 
CPU usage always goes up to 100% when running GRASS commands, while 
allocated memory is always about 25% -- flat, no peaks.
> A nice side effect of being built under those constraints is that now
> with more computing resources available it scales to huge datasets
> quite well.
>   
That's something I never considered -- interesting.
> So only worry if you are getting out-of-memory errors, otherwise just
> enjoy. It won't use any more or less memory than just the amount it
> needs.
>   
So in my case the CPU is very busy because of the Cygwin overload but 
the memory usage doesn't go up because of GRASS efficiency?

Kind regards,

Luigi
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