Re: [Openexr-devel] iif-optimisations branch tests

[Piotr Stanczyk]

Al Crate wrote:
> Hiya Piotr ... small world eh?!
indeed! :)
> Nope pulling from iif-optimisations branch, I'll check and see if 
> we've missed out the sse2 compiler flags or something.
We folded those changes into develop once we thought  the feature was 
ready for it.  If you have a chance, try timing just around the actual 
read to isolate from the rest of work needed.

> On 20/03/13 15:51, Piotr Stanczyk wrote:
> > Hey Al,
> >
> > Are you grabbing code from the develop branch?
> > There should be a input file method :
> >
> >      //---------------------------------------------------------------
> >      // Check if SSE optimization is enabled
> >      //
> >      // Call after setFrameBuffer() to query whether optimized file 
> > decoding
> >      // is available - decode times will be faster if returns true
> >      //
> >      // Optimization depends on:
> >      //   the file type (only scanline data is supported),
> >      //   the framebuffer channels (RGB/RGBA mono or stereo)
> >      //   the framebuffer channel types (all channels half-float 
> > format only)
> >      //   the file channels (RGB/RGBA mono or stereo)
> >      //   the file channel types (all channel half-float format only)
> >      //   whether SSE2 instruction support was detected at compile time
> >      //
> >      // Calling isOptimizationEnabled before setFrameBuffer will 
> > throw an exception
> >      //
> >      //---------------------------------------------------------------
> >
> > isOptimizationEnabled
> >
> > Can you run that and let me know what you are seeing?
> > The read times should indeed be mostly dominated by the 
> > (de)compressor workload. However, on my machine here I saw something 
> > in the region of 10-15% improvement.
> > Are you able to try this on an uncompressed file? You should see 
> > quite a significant speed up there.
> >
> > Let me know if that is not the case and we can look into this further.
> >
> > ________________________________________
> > From: address@hidden 
> > address@hidden on behalf of Al 
> > Crate address@hidden
> > Sent: 20 March 2013 03:32
> > To: address@hidden
> > Subject: [Openexr-devel] iif-optimisations branch tests
> >
> > Hi all,
> >
> > Just built the iff-optimised version, I tweaked the code in IlmImfTest
> > to spit out some timings between the aligned and unaligned tests.
> >
> > The timings are almost identical, which isn't what I'd expect, is there
> > anything I should be doing here to make this work, I also tried using
> > the optimised libraries in our playback tool and that showed little to
> > no speed improvements.
> >
> > I'm guessing I'm not using these correctly, is there some compiler
> > option I require or memory alignment needed?
> >
> > cheers
> >
> > al
> >
> >
> > _______________________________________________
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