Re: Whiteboard cacheing

[Alexander Larsson <alexl redhat com>]

On Fri, 2005-04-29 at 11:32 +0200, Alexander Larsson wrote:
> On Fri, 2005-04-29 at 11:25 +0200, Alexander Larsson wrote:
> > On Fri, 2005-04-29 at 10:20 +0200, Alexander Larsson wrote:
> > > The whiteboard cache changes didn't build for me, so i commited a fix
> > > that I think will work. Its untested though, because i can't seem to
> > > deploy without getting an OOM error atm.
> > > 
> > > Also, thinking about the caching during the night, wouldn't it make more
> > > sense to actually cache the png images on disk? That way we'd use less
> > > memory, let the kernel handle when and what to cache, and its still
> > > faster to read the thumbnail file from disk than regenerating the full
> > > image and then scaling it down. Especially since every client will be
> > > reading every thumbnail.
> > 
> > Also, looking at the current code it seems to not also create the
> > thumbnail when rendering the full image. It really should, because if
> > you load the full image you will always also need the thumbnail one, and
> > having to render the fullscale image twice (with the 1 megabyte
> > temporary buffers and other stuff being generated) is bad.
> > 
> > In fact, since after drawing a stroke the client is guaranteed to
> > request it i think it would make sense to render the initial versions in
> > the addStroke method call to avoid races for in what order to draw
> > thumbnail/full image.
> 
> Oh, i just noticed that we actually cache the full sized image in order
> to not redraw it again for the thumbnail. This is very bad, as this is
> very large (about one meg), while the pngs are very small (about 5-10K
> for a full image). 

I implemented this. However, we still create 7-8 megabyte of garbage
when you draw one stroke, even with only one client. We need to figure
out why that is happening.

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
 Alexander Larsson                                            Red Hat, Inc 
                   alexl redhat com    alla lysator liu se 
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