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Massimo B. Veteran
Joined: 09 Feb 2005 Posts: 1771 Location: PB, Germany
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Posted: Mon May 21, 2012 10:40 am Post subject: libjpeg-turbo on PPC |
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Code: | Title: The default JPEG implementation
Author: Samuli Suominen <ssuominen@gentoo.org>
Content-Type: text/plain
Posted: 2012-04-24
Revision: 1
News-Item-Format: 1.0
Display-If-Installed: =media-libs/jpeg-8*
libjpeg-turbo is a derivative of libjpeg that uses MMX, SSE, SSE2,
and NEON SIMD instructions to accelerate baseline JPEG
compression/decompression by about 2-4x on amd64, arm and x86
platforms. It is based on libjpeg/SIMD but has numerous enhancements.
All users are recommended to migrate:
# emerge --deselect media-libs/jpeg
# emerge --oneshot media-libs/libjpeg-turbo
media-libs/jpeg:0 will be left in tree as a fallback implementation. |
What does that mean for us? The only sentence about PPC I could found in the web was:
Quote: | libjpeg-turbo works on powerpc, but doesn't get any speedup over regular libjpeg. | Is that still correct? _________________ HP ZBook Power 15.6" G8 i7-11800H|HP EliteDesk 800G1 i7-4790|HP Compaq Pro 6300 i7-3770 |
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blob999 n00b
Joined: 07 Jun 2009 Posts: 64 Location: NATO area
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Posted: Mon May 21, 2012 1:57 pm Post subject: |
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that's right, there isn't any optimization for powerpc or altivec simd.
Jpeg optimizations with AltiVec exists only on macosx for powerpc. _________________ LinuxPPC user!
my blog: http://linuxpowerpc.blogspot.com/ |
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Massimo B. Veteran
Joined: 09 Feb 2005 Posts: 1771 Location: PB, Germany
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Posted: Mon May 21, 2012 2:09 pm Post subject: |
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Too bad again.. I would love to see some improvements on ppc too, but the arch is dying. Then most altivec optimizations such as glibc are only on MacOSX, can't we just use those ?
So migrating to libjpeg-turbo is advised on ppc too, even without performance gain? _________________ HP ZBook Power 15.6" G8 i7-11800H|HP EliteDesk 800G1 i7-4790|HP Compaq Pro 6300 i7-3770 |
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blob999 n00b
Joined: 07 Jun 2009 Posts: 64 Location: NATO area
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ssvb Tux's lil' helper
Joined: 06 Nov 2003 Posts: 96
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Posted: Fri May 25, 2012 9:14 pm Post subject: Re: libjpeg-turbo on PPC |
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Massimo B. wrote: |
What does that mean for us? The only sentence about PPC I could found in the web was:
Quote: | libjpeg-turbo works on powerpc, but doesn't get any speedup over regular libjpeg. | Is that still correct? |
Where did you find this statement? In any case, it does not matter You can easily run some jpeg decoding benchmarks with any image yourself. For example, on my playstation3 (with CFLAGS="-g -mcpu=cell -mtune=cell -maltivec -O2 -fomit-frame-pointer -pipe"):
Code: | # wget http://www.nasa.gov/images/content/618486main_earth_full.jpg
# emerge media-libs/jpeg-8d
# time djpeg 618486main_earth_full.jpg > /dev/null
real 0m5.298s
user 0m5.200s
sys 0m0.098s
# emerge ="media-libs/libjpeg-turbo-1.2.0-r1"
# time djpeg 618486main_earth_full.jpg > /dev/null
real 0m4.193s
user 0m4.096s
sys 0m0.095s
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Yes, libjpeg-turbo clearly can't be 2-4x times faster on PPC without altivec optimizations. But it still has some non-SIMD performance optimizations too (primarily huffman), which should give it some advantage on any platform. |
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Massimo B. Veteran
Joined: 09 Feb 2005 Posts: 1771 Location: PB, Germany
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Posted: Tue May 29, 2012 11:59 am Post subject: |
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Thank you. _________________ HP ZBook Power 15.6" G8 i7-11800H|HP EliteDesk 800G1 i7-4790|HP Compaq Pro 6300 i7-3770 |
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