Re: Speeding up thumbnail generation (like multi threaded). Thoughts please.

[Alexander Larsson <alexl redhat com>]

On Wed, 2009-09-30 at 14:53 +0200, Xavier Bestel wrote:
> Hi,
> 
> On Wed, 2009-09-30 at 11:46 +0200, Alexander Larsson wrote:
> > On Tue, 2009-09-29 at 22:59 +0200, Mark wrote:
> > 
> > > hehe that was the idea indeed ^_^ and i will continue with that.
> > > I will test the large factors tomorrow.
> > > 
> > > For now i'm happy with 100% cpu usage on all my cores (4).
> > > with the code posted in my previous message i only had 70% cpu usage
> > > so there was a bottleneck and it wasn't the HDD nor the CPU.
> > > Now that's fixed with giving each thread more then one (5 actually)
> > > images of it's own before locking and refilling the queue of 5 so now
> > > there is 100% cpu usage in the multi threaded benchmark.
> > > 
> > > http://codepad.org/PKnp69qW
> > 
> > Ok, i tested this a bit, and my results are not the same as yours.
> > 
> > I tested on a directory with 1348 jpeg files, each aroung 5 megapixels,
> > totalling 3.1 gig of data.
> 
> did you try testing with an already thumbnailed directory ? I find
> Nautilus quite slow in this case (sorry, I'm not at home right now do I
> can't test), although if I understand correctly there's not much work to
> do.

This benchmark was not nautilus, but a separate test app.

Nautilus being slow loading existing thumbnails is another thing. Partly
it is due to the way the thumbnail spec stores things (see the xdg list
for ways of making it better) and partly just loading lots of small
files being slow on rotating media.