PeerStreamer

optimization Tips (for libavcodec):

What to optimize:

If you plan to do non-x86 architecture specific optimizations (SIMD normally),

then take a look in the i386/ directory, as most important functions are

already optimized for MMX.

stuff in the i386 directory or find some other functions in the C source to

optimize, but there aren't many left.

Understanding these overoptimized functions:

As many functions tend to be a bit difficult to understand because

of optimizations, it can be hard to optimize them further, or write

architecture-specific versions. It is recommened to look at older

NOTE: If you still don't understand some function, ask at our mailing list!!!

(http://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-devel)

What speedup justifies an optimizetion?

Normaly with clean&simple optimizations and widely used codecs a overall

speedup of the affected codec of 0.1% is enough. These speedups accumulate

and can make a big difference after a while ...

WTF is that function good for ....:

The primary purpose of that list is to avoid wasting time to optimize functions

which are rarely used

Links:

http://www.aggregate.org/MAGIC/

x86-specific:

http://developer.intel.com/design/pentium4/manuals/248966.htm

The IA-32 Intel Architecture Software Developer's Manual, Volume 2:

ARM-specific:

ARM Architecture Reference Manual (up to ARMv5TE):

http://www.arm.com/community/university/eulaarmarm.html

http://download.intel.com/design/intelxscale/27347302.pdf

PowerPC-specific:

PowerPC32/AltiVec PIM:

www.freescale.com/files/32bit/doc/ref_manual/ALTIVECPEM.pdf

http://www-01.ibm.com/chips/techlib/techlib.nsf/techdocs/9F820A5FFA3ECE8C8725716A0062585F/$file/CBE_Handbook_v1.1_24APR2007_pub.pdf

SPARC-specific:

SPARC Joint Programming Specification (JPS1): Commonality

http://www.fujitsu.com/downloads/PRMPWR/JPS1-R1.0.4-Common-pub.pdf

http://www.sun.com/processors/vis/download/vis/vis_whitepaper.pdf

GCC asm links:

official doc but quite ugly

http://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html