simple optimization instead of asynchronous upload

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simple optimization instead of asynchronous upload

Łukasz Stelmach
Hello.

I've set up T@H yesterday and noticed a small efficiency problem with a
forked setup. tilesGen.pl starts with a single, simple z12 256x256 tile
and goes towards more complex pictures. This leaves it with a *single* z17
inkscape trying hard. It would be much more efficient if z17 was the
first zoom levevel to deal with because (lets assume a spherical cow)

Let Fork equal 2.
Let time(z_n)=4*time(z_{n-1})
If time(z_12) = 1 then time(z_12..z16) = 341 and time(z17) = 1024

If the first thread starts with z17 then the other can do all other
levels in parallel

If time(z_n) = 2*time(z_{n-1})
   then
time(z_12..z16) = time(z17)-time(z_12)

--
Łukasz Stelmach


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Re: simple optimization instead of asynchronous upload

Dirk-Lüder Kreie
Am 07.02.2011 12:06, schrieb Łukasz Stelmach:

> Hello.
>
> I've set up T@H yesterday and noticed a small efficiency problem with a
> forked setup. tilesGen.pl starts with a single, simple z12 256x256 tile
> and goes towards more complex pictures. This leaves it with a *single* z17
> inkscape trying hard. It would be much more efficient if z17 was the
> first zoom levevel to deal with because (lets assume a spherical cow)
>
> Let Fork equal 2.
> Let time(z_n)=4*time(z_{n-1})
> If time(z_12) = 1 then time(z_12..z16) = 341 and time(z17) = 1024
>
> If the first thread starts with z17 then the other can do all other
> levels in parallel
>
> If time(z_n) = 2*time(z_{n-1})
>    then
> time(z_12..z16) = time(z17)-time(z_12)
>
Short answer:

It makes sense to run the z17 thread alone, because it's not cpu but RAM
bound.


--
Dirk-Lüder "Deelkar" Kreie
Bremen - 53.0901°N 8.7868°E

Ceterum censeo Carthaginem esse delendam.


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Re: simple optimization instead of asynchronous upload

spaetz
On Mon, 07 Feb 2011 13:59:05 +0100, Dirk-Lüder Kreie <[hidden email]> wrote:
> > If the first thread starts with z17 then the other can do all other
> > levels in parallel

> It makes sense to run the z17 thread alone, because it's not cpu but RAM
> bound.

You don't want to run z17 rendering in parallel to anything else,
believe me :-). If there are problems, this is where they will occur.

Sebastian

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