[sldev] AppendedAcks

[Teravus Ovares]

In testing with OpenSimulator, I note, that there doesn't seem to be a
problem with the disk texture cache.   In fact, the persistant cache
often makes it more difficult to notice when there is a problem with
the texture sender.  People don't start noticing an issue until they
clear their client cache.   Before they do that, everything seems
normal to the client even if the textures don't exist anymore.

Best Regards

Teravus

On 4/2/09, Dale Mahalko <dmahalko at gmail.com> wrote:
> On Thu, Apr 2, 2009 at 9:51 AM, Carlo Wood <carlo at alinoe.com> wrote:
> > I'm sure I have my cache not a single byte smaller than most
> > people (I have the slider all the way to the max, 1 GB), but
> > everytime I go to a new sim and then return home, everything
> > is gray and apparently has to be re-downloaded.
> >
>
> What you're seeing is discarding from the decompressed texture cache,
> not from the on-disk texture cache.
>
> There is a hidden texture cache in memory that never gets written to
> disk, which contains raw RGB bitmaps of the JPEG2000 data. It is never
> written to disk apparently for obfuscation purposes.
>
>
> I have never delved deep enough to determine if this raw bitmap cache
> is part of the 3D card's texture cache, or if it is an entire
> duplication of the 3D VRAM cache.
>
> So, you have the following hogging system memory with the client running:
> - Operating system
> - Client software
> - VFS cache that is held fully in memory all the time
> - Hidden decompressed raw bitmap texture cache of unknown size
> - (possibly separate?) 3D card texture caching
>
>
> When you teleport somewhere, it was previously reported by someone
> here on SLDev that the decompressed raw-bitmap image cache is
> completely dumped, and then the world must be completely
> re-decompressed from the JPEG2000's on disk, which is extremely slow
> and CPU intensive.
>
> This is why the world appears gray anytime you teleport. It simply
> threw all the previous decoded texture data away and starts redecoding
> anew.
>
> - Scalar Tardis / Dale Mahalko
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