[FFmpeg-devel] Anybody has a Core 2? [PATCH] Small SSSE3 optimization

Michael Niedermayer michaelni
Wed May 9 16:09:11 CEST 2007


Hi

On Wed, May 09, 2007 at 06:16:36PM +0800, Zuxy Meng wrote:
> Hi,
> 
> 2007/5/9, Guillaume POIRIER <poirierg at gmail.com>:
> > Hi,
> >
> > On 5/9/07, Zuxy Meng <zuxy.meng at gmail.com> wrote:
> > > Hi,
> > >
> > > 2007/5/8, Zuxy Meng <zuxy.meng at gmail.com>:
> > > > Hi,
> > > >
> > > > Attached patch makes use of SSSE3 instruction pabsw to calculate the
> > > > absolute value of packed words. Just for fun. And I don't have a SSSE3
> > > > capable CPU so hopefully someone with a Core 2 can help test it to
> > > > ensure it doesn't break anything (better with benchmarks of course:-)
> > > > ).
> > >
> > >
> > > Updated patch against curren SVN HEAD. Full test passed on MMX2. Of
> > > course it still needs testing under Core 2.
> >
> > cat /proc/cpuinfo
> > processor       : 0
> > vendor_id       : GenuineIntel
> > cpu family      : 6
> > model           : 15
> > model name      : Intel(R) Xeon(R) CPU            5130  @ 2.00GHz
> > stepping        : 6
> > cpu MHz         : 2000.055
> > cache size      : 4096 KB
> > physical id     : 0
> > siblings        : 2
> > core id         : 0
> > cpu cores       : 2
> > fpu             : yes
> > fpu_exception   : yes
> > cpuid level     : 10
> > wp              : yes
> > flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge
> > mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm syscall
> > nx lm constant_tsc pni monitor ds_cpl vmx tm2 cx16 xtpr lahf_lm
> > bogomips        : 4003.24
> > clflush size    : 64
> > cache_alignment : 64
> > address sizes   : 36 bits physical, 48 bits virtual
> >
> > [...]
> >
> > make codectest passes, make test passes, make fulltest passes.
> >
> > \o/ !!
> 
> Cool! Can u do a small unit-test to compare the MMX2 and SSSE3 version
> of hadamard8_diff? Intel don't give the latency of pabsw in their
> manuals (while AMD always give ALL instructions' latency & throughput)

see http://www.agner.org/optimize/instruction_tables.pdf

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Concerning the gods, I have no means of knowing whether they exist or not
or of what sort they may be, because of the obscurity of the subject, and
the brevity of human life -- Protagoras
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