On Thu, Oct 27, 2011 at 10:30:14PM +0300, Siarhei Siamashka wrote: > On Thu, Oct 27, 2011 at 9:45 PM, Christian Robottom Reis > <k...@linaro.org> wrote: > > On Wed, Oct 26, 2011 at 03:54:52PM -0500, Tom Gall wrote: > >> Hardware used includes the imx53 QuickStart board by freescale and an > >> intel core 2 duo in my Lenovo T400. > >> > >> The results can be found here including both the raw numbers and pretty > >> graphs. > >> > >> https://wiki.linaro.org/TomGall/LibJpeg8 > > > > Again, wow, thanks for such a thorough analysis. I think this is indeed > > very good material for discusing with Ubuntu. Do we have a session > > scheduled with them to talk about this? > > > > I have a question: any idea why the gap between 8c and turbo8 is so much > > more impressive on x86(_64) than on ARM? > > Out of curiosity, how much is "much more impressive"? Which case in > particular has caught your attention?
Sorry; here's the graphs which show where I was surprised to see a 3-4x gap: https://wiki.linaro.org/TomGall/LibJpeg8?action=AttachFile&do=view&target=Intel-x86_64-3136x2352-Q95-libjpeg8vlibjpeg-turbo.jpg https://wiki.linaro.org/TomGall/LibJpeg8?action=AttachFile&do=view&target=Intel-x86_64-3136x2352-Q75-libjpeg8vlibjpeg-turbo.jpg https://wiki.linaro.org/TomGall/LibJpeg8?action=AttachFile&do=view&target=Intel-x86_64-640x480-Q75-libjpeg8vlibjpeg-turbo.jpg https://wiki.linaro.org/TomGall/LibJpeg8?action=AttachFile&do=view&target=Intel-x86_64-640x480-Q95-libjpeg8vlibjpeg-turbo.jpg > > Could there be low-hanging fruit left in the NEON codepaths? > > Yes, currently missing ARM NEON optimizations for chroma > upsampling/downsampling and grayscale color conversions definitely > affect the tjbench results for subsampled formats and grayscale. > > Also huffman decoder optimizations (which are C code, not SIMD) in > libjpeg-turbo seem to be providing only some barely measurable > improvement on ARM, while huffman speedup is clearly more impressive > on x86. This gives libjpeg-turbo more points over IJG jpeg on x86 as a > result. We should definitely consider these for future work, then. Thanks for the reply, -- Christian Robottom Reis, Engineering VP Brazil (GMT-3) | [+55] 16 9112 6430 | [+1] 612 216 4935 Linaro.org: Open Source Software for ARM SoCs _______________________________________________ linaro-dev mailing list linaro-dev@lists.linaro.org http://lists.linaro.org/mailman/listinfo/linaro-dev