[FFmpeg-devel] [PATCH] ffvorbis, better L1 cache use and simplification of code
Wed Oct 1 02:22:51 CEST 2008
On Tuesday 30 September 2008, Benoit Fouet wrote:
> Siarhei Siamashka wrote:
> > Interleaved forward/backward channels processing in order to increase
> > chances of stepping on already cached data for the cores with extremely
> > small data cache. Ensure that IMDCT per-rotation does not introduce cache
> > write misses (write misses on random memory accesses are bad for ARM
> > cores with no write-allocate cache as they prevent combining data in the
> > write buffer).
> > ARM11 with 32K of L1 data cache (no L2) shows performance improvement in
> > the range 0.5-1% which is not so bad considering that IMDCT/IFFT and also
> > many other important dsputil functions are not assembly optimized for it
> > yet.
> > According to cachegrind simulation, there might be also some improvement
> > for x86 cores with 16K of L1 data cache (decrease of the number of cache
> > misses is most visible in this configuration).
> does this patch depend on another one I missed ?
It's a single selfcontained patch.
> it doesn't apply as is...
It doesn't apply to what? Patch was generated against FFmpeg revision 15451,
but also applies fine to revision 15492 which is current SVN HEAD.
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