[vorbis-dev] vorbis on playstation 2
nico at cam.org
Thu Feb 6 17:31:14 PST 2003
On Thu, 6 Feb 2003, David Etherton wrote:
> > > 44% mdct_backward
> > > 10% _vorbis_apply_window
> > > 9% vorbis_book_decodevv_add
> > This is obviously cache kill. Note that the mdct itself is not the
> > only culprit of that, of course.
> Interesting. I turned on _LOW_ACCURACY_ and rebuilt the library and the
> total cycle count for my test case went from 950M cycles to 723M cycles.
> The two sincos lookup tables are 4K each in "full" mode which are likely
> going to thrash the cache.
Depending on the stream used, the second table is unlikely to be referenced.
> I could move the whole LUT into scratchpad easily enough (some of our
> low-precision character animation uses a small lut in scratchpad already, it
> was a pretty good win) although I'd like to trim the table down a bit.
> Would I be better off going to a signed short to cut the table size in half
> or just cut the number of entries in half?
If you used _LOW_ACCURACY_ the sincos tables were compiled as unsigned char
--- >8 ----
List archives: http://www.xiph.org/archives/
Ogg project homepage: http://www.xiph.org/ogg/
To unsubscribe from this list, send a message to 'vorbis-dev-request at xiph.org'
containing only the word 'unsubscribe' in the body. No subject is needed.
Unsubscribe messages sent to the list will be ignored/filtered.
More information about the Vorbis-dev